# Biotin (vitamin B7), sole-active oral product × Reduction of recurrent brittle-nail breakage events over a standardized observation period Verdict 3104 · Evidence Check Stored-material review date: 2026-10-05 Original evidence date: 2026-09-15 Review-criteria version: NGM-v3104-BIOTIN-RECURRENT-NAIL-BREAKAGE-1.2 Public page/material preparation date: 2026-11-03 Clinical papers were not read directly; existing review summaries were checked. No new clinical-literature search was performed. Unverified does not mean that research is absent or that there is no effect. ## Assessment scope - Population: Adults with general brittle nails, with separate fingernail and toenail strata; confirmed deficiency correction and specific secondary causes excluded; unreported biotin status not presumed normal - Ingredient, formulation and route: Biotin (biotin, vitamin B7), sole active ingredient · The question is bounded to a sole-active oral product; tablet or capsule, excipients, batch, and purity unverified · Oral; topical use, injection, and effects of topical products themselves excluded - Dose: Unverified — eligible regimen dose, dosing frequency, and total dietary and concurrent supplement intake - Comparator: Placebo, no-treatment, and usual-care comparisons with the same background conditions are each preserved; the actual eligible comparator is unverified - Measured outcome: Between-group change difference or difference in event counts over the same prespecified period; event rates treated separately when exposure time is verified; distinguished from thickness, hardness, PGA, and OGSS - Duration: Unverified — the actual treatment duration and the prespecified breakage observation period each require verification - Questions outside this scope: Confirmed deficiency correction and specific secondary causes; topical use, injection, and effects of topical products themselves; products with multiple or other active ingredients; and thickness, growth, hardness, surface, photographs, PGA, OGSS, and satisfaction are excluded from this recurrent breakage-event question. Fingernails and toenails are not pooled, and comparisons of biotin added to the same topical care are distinguished as conditional add-on effects. ## Checklist items ### N01 · Does this table address a single question about recurrent breakage events per person with oral biotin alone? Verification status: Met Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The original claim is a reduction in brittle-nail breakage-event frequency over a standardized observation period. The table selects the between-group recurrent-event-count question for oral biotin as the sole active ingredient and separates thickness, growth, hardness, PGA, OGSS, and satisfaction. - Why unverified: The currently retained original claim, crux, and facets specify the same selected question. This verifies the identity of the question, not an actual effect. - Reason for missing information: Directly eligible breakage-event results, measurement definitions, periods, and effect values remain unverified. - Required materials and conditions: Exact original wording of the current claim, population, ingredient, route, comparator, and recurrent-event endpoint - Materials to obtain first: Exact original wording of the current claim, population, ingredient, route, comparator, and recurrent-event endpoint - Further research: In a comparative study with a fixed question, prespecify the event definition and observation period and separate estimates by site. - Conditions for verification: Link the same question as in the original /ko/effect and specify event counts per person over a prespecified period and the excluded endpoints. - Why this condition is needed: Needed to avoid combining improved thickness or hardness and reduced breakage counts as the same efficacy outcome. - Application exceptions: Fingernails and toenails remain separate strata. The fact that direct results are currently unverified does not by itself justify creating a new, separate completed table for each stratum. - Remaining uncertainty: Directly eligible breakage-event results, measurement definitions, periods, and effect values remain unverified. - Referenced methods: M03 §3.1, §3.2.1–3.2.4 question-clarification principles; detailed separation rules are internally designed; M03 §3.2.2–3.2.3; reverse-direction marking and test adaptations are internally designed; M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M03 §3.2.4; internally designed extension boundary - Related sources: ### N02 · Is biotin the only additional active ingredient in the actual study product? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The question concerns oral biotin alone. Chiavetta compares biotin added to the same lacquer, but the endpoint differs. Patel's biotin-labeled arm uses Sesbania extract, and a sole-active-ingredient effect was not isolated. - Why unverified: The common lacquer and plant-extract differences in the actual materials were verified, but a product in an eligible recurrent-event comparison was not verified. - Reason for missing information: The eligible formulation's composition, chemical form, purity, batch, and the contribution of biotin alone are unverified. - Required materials and conditions: Original text on product composition, active ingredients, background treatment, and batch by arm - Materials to obtain first: Original text on product composition, active ingredients, background treatment, and batch by arm - Further research: Design a comparison that keeps active ingredients other than biotin and background care identical, and disclose product composition. - Conditions for verification: Indicate the sole-active question and the differences between actual products with a sole active ingredient, combinations, and a common background treatment. - Why this condition is needed: Needed to avoid attributing the effects of other active ingredients in a biotin-labeled product to biotin alone. - Application exceptions: If both arms receive the same background topical product, retain the comparison as a candidate for the add-on effect of biotin. Do not recast a plant extract itself as pure biotin. - Remaining uncertainty: The eligible formulation's composition, chemical form, purity, batch, and the contribution of biotin alone are unverified. - Referenced methods: M03 §3.2.2–3.2.3; reverse-direction marking and test adaptations are internally designed; M03 §3.2.3, M08 §8.2.2–8.2.3; internal application - Related sources: S24, S05 ### N03 · Was an eligible sole-active product used whose chemical form, source, tablet/capsule form, excipients, and batch were verified? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The chemical form, source, tablet/capsule form, excipients, batch, and purity of the current eligible formulation are all retained as not_verified with null values. - Why unverified: The question's sole-active-product boundary is known, but identity data for an actual formulation with direct event results are unavailable. - Reason for missing information: Actual analytical and batch information for the eligible product is unverified. - Required materials and conditions: Chemical form, manufacturing source, dosage form, excipients, and batch/purity records for the eligible product - Materials to obtain first: Chemical form, manufacturing source, dosage form, excipients, and batch/purity records for the eligible product - Further research: Obtain quantitative content, purity, and dosage-form data for the same batch in a comparative study, and track differences other than the active ingredient. - Conditions for verification: Link only verified product identity information and preserve the null values in actual_trial_fields. - Why this condition is needed: Needed to avoid concealing an unverified product identity behind an assumption that the biotin formulations are identical. - Application exceptions: The word biotin in a bibliographic title does not establish the exact chemical form or purity. Do not invent an unknown brand to fill the gap. - Remaining uncertainty: Actual analytical and batch information for the eligible product is unverified. - Referenced methods: M03 §3.2.2–3.2.3; reverse-direction marking and test adaptations are internally designed - Related sources: ### N04 · Were the original dose and the actual dosing frequency, dietary intake, and concurrent supplements contributing to total exposure distinguished? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Floersheim's 2.5 mg/day and Chiavetta's 10 mg/day remain in the original text. The former concerns a hardness response, and the latter compares severity with biotin added to the same lacquer; the dose, dosing frequency, and dietary/concurrent supplement intake for an eligible breakage-event regimen are null. - Why unverified: The stated doses in the two materials are verified, but they do not establish an effective dose or total exposure for the target breakage events. - Reason for missing information: The eligible dose, dosing frequency, total dietary/supplement intake, and dose–effect relationship are unverified. - Required materials and conditions: Dose, dosing frequency, administration records, dietary/concurrent supplement intake, and actual exposure - Materials to obtain first: Dose, dosing frequency, administration records, dietary/concurrent supplement intake, and actual exposure - Further research: If dose-specific questions are needed in a direct comparison that collects total exposure and adherence, design them separately in advance. - Conditions for verification: Distinguish each study's originally stated dose from the unverified eligible regimen. - Why this condition is needed: Needed to avoid recasting a nominal dose from another regimen as an effective dose for reducing breakage frequency. - Application exceptions: Preserve the original studies' 2.5 mg/day and 10 mg/day, but do not perform new conversions, identify an optimal dose, or give individual dosing recommendations. - Remaining uncertainty: The eligible dose, dosing frequency, total dietary/supplement intake, and dose–effect relationship are unverified. - Referenced methods: M03 §3.2.2–3.2.3; reverse-direction marking and test adaptations are internally designed; M03 §3.2.1–3.2.4; details concerning dose, persistence, and effect modification are internally designed - Related sources: S23, S24 ### N05 · Are the treatment duration and the prespecified observation period for counting recurrent breakage each verified? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Floersheim's mean of 5.5 ± 2.3 months and Chiavetta's 4 months of treatment remain recorded, but the prespecified observation period and individual exposure time for eligible recurrent breakage events were not verified. - Why unverified: Treatment duration alone does not meet the condition of a defined observation window for recurrent events. - Reason for missing information: An identical event observation period, complete follow-up, and individual observation times are unverified. - Required materials and conditions: Treatment start/end, prespecified event observation window, and follow-up/missingness records at each time point - Materials to obtain first: Treatment start/end, prespecified event observation window, and follow-up/missingness records at each time point - Further research: Set the same observation window for both arms and collect individual observation time and discontinuation/missingness data to distinguish event counts from event rates. - Conditions for verification: Link treatment duration, event observation period, and exposure time as separate items. - Why this condition is needed: Needed to prevent the number of treatment months from being used as event observation time. - Application exceptions: Preserve study treatment durations, but do not assume that events were captured completely during those periods. - Remaining uncertainty: An identical event observation period, complete follow-up, and individual observation times are unverified. - Referenced methods: M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M08 Table 8.2.a, M15 §15.3, M19 §19.1.2–19.2.4; design-specific adaptations are internally designed; M03 §3.2.1–3.2.4; details concerning dose, persistence, and effect modification are internally designed - Related sources: S23, S24 ### N06 · Do the actual diagnoses and severity in the materials match adults with general brittle nails? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The question is fixed to adults with general brittle nails and excludes confirmed deficiency correction and specific disease, trauma, or drug-related causes. Actual eligible diagnostic criteria and baseline severity are not_verified. - Why unverified: The question's population boundary has been preserved, but actual participant selection criteria for a direct event study are unavailable. - Reason for missing information: Diagnosis, baseline severity, exclusion of secondary causes, and representativeness are unverified. - Required materials and conditions: Age, diagnosis/severity, inclusion/exclusion, secondary causes, and the composition of mixed populations - Materials to obtain first: Age, diagnosis/severity, inclusion/exclusion, secondary causes, and the composition of mixed populations - Further research: Report selection flow and baseline characteristics by site in a population whose secondary causes and severity have been verified. - Conditions for verification: Distinguish the question's scope of general adults, how the actual population matches it, and exclusions that could not be verified. - Why this condition is needed: Needed to avoid pooling other secondary disease, trauma, or drug-related causes with general brittle nails. - Application exceptions: Retain mixed populations as well, but leave direct applicability unverified when population composition or separate results are unavailable. - Remaining uncertainty: Diagnosis, baseline severity, exclusion of secondary causes, and representativeness are unverified. - Referenced methods: M03 §3.2.1; detailed population conditions are internally designed - Related sources: ### N07 · Are baseline biotin testing and the method used to determine deficiency verified? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The original text explicitly states that unreported baseline biotin status is not presumed to mean absence of deficiency. baseline_biotin, deficiency_assay, and dietary_biotin remain null. - Why unverified: Baseline biotin status and deficiency classification in the direct breakage-event population were not verified. - Reason for missing information: Baseline status, assay methods, and applicable deficiency criteria are unverified. - Required materials and conditions: Baseline testing, deficiency definition, diet, concurrent supplements, and whether confirmed deficiency was corrected - Materials to obtain first: Baseline testing, deficiency definition, diet, concurrent supplements, and whether confirmed deficiency was corrected - Further research: Record the assay method and classification criteria and analyze the deficiency-correction stratum separately, without making arbitrary subgroup efficacy determinations. - Conditions for verification: Distinguish actually measured status from unreported status, and do not invent an arbitrary criterion for normality. - Why this condition is needed: Needed to avoid treating an unreported status as normal or nondeficient. - Application exceptions: Separate confirmed deficiency correction from this general brittle-nail question. Retain applicability limitations without deleting all data from participants whose status was not measured. - Remaining uncertainty: Baseline status, assay methods, and applicable deficiency criteria are unverified. - Referenced methods: M03 §3.2.1; detailed population conditions are internally designed; M03 §3.2.2–3.2.3; reverse-direction marking and test adaptations are internally designed - Related sources: ### N08 · Are the actual observed sites, numbers observed, and direct recurrent breakage-event results verified separately for fingernails and toenails? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The two strata, fingernails and toenails, have direct_result_verified=false and effect=null. Chiavetta is retained as great-toenail severity data and was not transferred to fingernail event frequency. - Why unverified: The question's site strata and the location of the great-toenail data are verified, but no direct recurrent-event effect in either stratum was verified. - Reason for missing information: Fingernail/toenail-specific event results, denominators, and effects, and the actual number of nails observed, are unverified. - Required materials and conditions: Fingernails/toenails, target sites, numbers observed, and site-specific results and denominators - Materials to obtain first: Fingernails/toenails, target sites, numbers observed, and site-specific results and denominators - Further research: Prespecify event definitions and measurements by site, and plan appropriate stratified comparisons and interaction analyses. - Conditions for verification: Check the extent of verification of actual observed sites, numbers of nails, and site-specific recurrent-event results and denominators. Distinguish materials in which only great-toenail severity was verified from the gap in direct event results by site. - Why this condition is needed: Needed to avoid transferring great-toenail severity results to fingernail breakage frequency. - Application exceptions: Retain null values when direct results by site are unavailable, and do not mechanically produce two completed tables. - Remaining uncertainty: Fingernail/toenail-specific event results, denominators, and effects, and the actual number of nails observed, are unverified. - Referenced methods: M03 §3.2.1; detailed population conditions are internally designed; M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M03 §3.2.1–3.2.4; details concerning dose, persistence, and effect modification are internally designed - Related sources: S24 ### N09 · Were the breakage-event definition, collection method, and recurrent-event recording fixed in advance? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The primary endpoint of breakage-event counts per person over a prespecified period is stated at the question level. The actual eligible event definition, observation window, and collection method are null; PGA, OGSS, thickness, and hardness do not replace them. - Why unverified: The exact actual method for collecting recurrent events is absent from the current input. - Reason for missing information: Event identification, duplicate recording of the same event, differentiation of new breakage, measurement validation, and arm-specific procedures are unverified. - Required materials and conditions: Event identification, distinction between recurrent/new events, recording intervals, validation, and assessor blinding - Materials to obtain first: Event identification, distinction between recurrent/new events, recording intervals, validation, and assessor blinding - Further research: Use identical event definitions and diary/validation procedures, and manage recurrent-event recording, duplicate entries, and missing measurements. - Conditions for verification: Clearly distinguish recurrent breakage events per person from severity and responder measures. - Why this condition is needed: Needed to avoid converting splitting presence or severity scores into event counts. - Application exceptions: Subjective event reports may also be retained, but their actual definitions and measurement limitations must be disclosed. Do not impose blinding unconditionally. - Remaining uncertainty: Event identification, duplicate recording of the same event, differentiation of new breakage, measurement validation, and arm-specific procedures are unverified. - Referenced methods: M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M08 Table 8.2.a, M03 §3.2.4; internal application - Related sources: S05 ### N10 · Were the numbers of people allocated and analyzed, the number of nails observed, and recurrent-event counts distinguished? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: In actual_trial_fields, randomized_n, analysis_n, completed_n, and number_of_nails_observed are null. The n field in evidence is a reference to a separate numeric_evidence table, and that table is absent from this input. - Why unverified: There are insufficient data to connect the denominators described for each study with the analysis denominators for direct breakage events. - Reason for missing information: Event/person counts, nail counts, individual follow-up time, and actual arm-specific analysis/completer denominators are unverified. - Required materials and conditions: Arm-specific counts of people allocated/analyzed/completing follow-up, nails, and events, and observation time - Materials to obtain first: Arm-specific counts of people allocated/analyzed/completing follow-up, nails, and events, and observation time - Further research: Record clustering and recurrence structures for people and nails, and prespecify an analysis denominator suited to the effect of interest. - Conditions for verification: Use only the denominator types supplied by the current input and preserve eligible-event denominators as null. - Why this condition is needed: Needed to avoid converting the number of evaluable people into a denominator for observed nails, events, or event rates. - Application exceptions: Preserve the denominators in case materials and abstracts, but do not calculate unavailable event counts, exposure time, or CIs. - Remaining uncertainty: Event/person counts, nail counts, individual follow-up time, and actual arm-specific analysis/completer denominators are unverified. - Referenced methods: M08 Table 8.2.a, M15 §15.3, M19 §19.1.2–19.2.4; design-specific adaptations are internally designed; M08 §8.2.2, M15 §15.3.1; internal application - Related sources: S20, S24, S05 ### N11 · Are within-group before–after comparisons and the direction of the actual comparison for added biotin distinguished? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Colombo and Hochman are nonrandomized/uncontrolled before–after and response evaluations. Chiavetta is a randomized comparison of biotin added to the same lacquer, but uses a severity endpoint. A direct between-group comparison of breakage events is unverified. - Why unverified: The actual contrasts in prior materials can be distinguished, but there is no direct comparison for the selected event endpoint. - Reason for missing information: Eligible placebo, no-treatment, and usual-care comparisons and the effect of interest are unverified. - Required materials and conditions: Design, actual added ingredients by arm, comparator, and direction of between-group/within-group estimation - Materials to obtain first: Design, actual added ingredients by arm, comparator, and direction of between-group/within-group estimation - Further research: Prespecify the effect of assignment and the direction of analysis in a comparison that maintains identical background care. - Conditions for verification: Record within-group before–after comparisons, conditional add-on comparisons, and independent controls separately; do not present a planned comparison as an actual comparison. - Why this condition is needed: Needed to avoid presenting before–after improvement as a between-group causal effect. - Application exceptions: Retain add-on comparisons with common topical care, while specifying the effect of interest and the differing endpoint. - Remaining uncertainty: Eligible placebo, no-treatment, and usual-care comparisons and the effect of interest are unverified. - Referenced methods: M03 §3.2.2–3.2.3; reverse-direction marking and test adaptations are internally designed; M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M08 §8.1–8.2.3; internal application; M08 §8.2.2, M15 §15.3.1; internal application - Related sources: S20, S21, S24 ### N12 · Do Colombo's thickness and surface data provide controlled recurrent breakage-event results for biotin alone? Verification status: Not met Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Colombo 1990 is a nonrandomized before–after electron-microscopy observation. The retained English design description explicitly states that the healthy comparator is not a matched randomized treatment control; the endpoints are thickness and surface structure. - Why unverified: The currently verified endpoint and treatment comparator do not meet the selected between-group recurrent breakage-event conditions. - Reason for missing information: Target breakage-event counts, a comparator with the same background treatment, and denominators/observation windows are unverified. - Required materials and conditions: Colombo's actual design, surface/thickness measurements, treatment comparator, and event records - Materials to obtain first: Colombo's actual design, surface/thickness measurements, treatment comparator, and event records - Further research: In a comparison that collects both thickness and recurrent events, estimate endpoint-specific results and their relationship separately. - Conditions for verification: Check whether the actual ingredient, treatment comparator, and endpoint meet the direct recurrent-event conditions, and preserve the original thickness and surface results. - Why this condition is needed: Needed to distinguish structural and thickness changes from recurrent breakage events. - Application exceptions: Even if healthy comparators are present, verify whether they constitute the same treatment-assignment control. Do not label an older study as a newly read full text. - Remaining uncertainty: Target breakage-event counts, a comparator with the same background treatment, and denominators/observation windows are unverified. - Referenced methods: M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M08 §8.1–8.2.3; internal application; M03 §3.2.4; internally designed extension boundary - Related sources: S20 ### N13 · Does Hochman's response evaluation provide controlled recurrent breakage-event results over a prespecified period? Verification status: Not met Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Hochman 1993 is a retrospective uncontrolled response evaluation. Subjective improvements in hardness and splitting are preserved, but a control group and time denominators for events were not verified. - Why unverified: The response evaluation does not provide the selected controlled recurrent-event-count results. - Reason for missing information: The original number of people analyzed, recurrent breakage counts, observation time, and comparator are unverified in the current input. - Required materials and conditions: Original response criteria, participant selection, recall period, comparator, and recurrent-event records - Materials to obtain first: Original response criteria, participant selection, recall period, comparator, and recurrent-event records - Further research: Use the same prospectively specified event definition and observation period, and plan the comparator and handling of missing data. - Conditions for verification: Compare response criteria, comparator, and observation period with the selected recurrent-event conditions, and preserve mismatched endpoints in their original role. - Why this condition is needed: Needed to avoid elevating reports of improved hardness or splitting to prospectively specified event records. - Application exceptions: Retain retrospective uncontrolled data as signals and descriptive material, and do not fill in absent time denominators for events. - Remaining uncertainty: The original number of people analyzed, recurrent breakage counts, observation time, and comparator are unverified in the current input. - Referenced methods: M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M08 Table 8.2.a, M15 §15.3, M19 §19.1.2–19.2.4; design-specific adaptations are internally designed; M08 §8.1–8.2.3; internal application; M08 §8.2.2, M15 §15.3.1; internal application - Related sources: S21 ### N14 · In the report of 71 people treated, 45 evaluated, and 41 reporting improved hardness, are the reasons for exclusion from evaluation and the analysis denominators for recurrent breakage events verified? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Floersheim reported that, after treatment of 71 people, the 45 evaluable people included 41 with improved firmness/hardness. The 41 is a count of people who improved, not a count of recurrent breakage events per person. - Why unverified: The numbers of people treated, evaluated, and responding are verified, but target recurrent-event denominators and reasons for missing data are unavailable. - Reason for missing information: Reasons why participants were not evaluated, the number of nails observed, event counts, and the comparator are unverified. - Required materials and conditions: Original data on treated/evaluated/responder denominators, reasons for exclusion, event counts, and comparator - Materials to obtain first: Original data on treated/evaluated/responder denominators, reasons for exclusion, event counts, and comparator - Further research: Report follow-up and reasons for exclusion from evaluation for all allocated participants, and prespecify the recurrent-event analysis population. - Conditions for verification: Attribute 71, 45, and 41 to their original-text roles as treated, evaluated, and hardness responders, and assess the extent to which reasons for exclusion from evaluation, numbers of nails observed, recurrent-event denominators, and the comparator are verified by actual data. Do not convert person counts into event counts. - Why this condition is needed: Needed to avoid expressing 41 people as a reduction in recurrent-event counts or generalizing a proportion among evaluated people to an effect among everyone treated. - Application exceptions: Retain the person counts in the abstract, but do not infer reasons for exclusion from evaluation or calculate between-group effects or event rates. - Remaining uncertainty: Reasons why participants were not evaluated, the number of nails observed, event counts, and the comparator are unverified. - Referenced methods: M08 Table 8.2.a, M15 §15.3, M19 §19.1.2–19.2.4; design-specific adaptations are internally designed; M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M08 §8.2.2, M15 §15.3.1; internal application - Related sources: S23 ### N15 · For the report of 2.5 mg/day and a mean of 5.5 ± 2.3 months, are actual exposure records, the definition of ±, and the prespecified breakage observation period verified? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The currently retained abstract summary reports 2.5 mg/day and a mean of 5.5 ± 2.3 months. The type of ±, a diary, a placebo comparison, and a standardized event window were not verified in the abstract. - Why unverified: The stated dose and mean duration were verified, but the type of dispersion and event observation conditions were not verified. - Reason for missing information: Whether ± denotes SD, SE, or another range, and the actual breakage observation window and adherence, are unverified. - Required materials and conditions: Original dose and duration, definition of ±, observation window, and administration records - Materials to obtain first: Original dose and duration, definition of ±, observation window, and administration records - Further research: Specify treatment duration and the event observation window separately, and report actual exposure records and an explanation of dispersion. - Conditions for verification: Preserve the original dose and mean treatment duration while checking the extent of verification of the type of ±, actual administration records, and the prespecified breakage observation period. Do not assume that the treatment duration's ± is an SD, SE, CI, or standardized event observation window. - Why this condition is needed: Needed to avoid interpreting the ± accompanying variable treatment duration as an SD/SE/CI or a standardized event observation window. - Application exceptions: If the type of ± is not verified in the abstract, retain it as unverified. Do not indicate that the original German full text was read. - Remaining uncertainty: Whether ± denotes SD, SE, or another range, and the actual breakage observation window and adherence, are unverified. - Referenced methods: M03 §3.2.2–3.2.3; reverse-direction marking and test adaptations are internally designed; M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M08 Table 8.2.a, M15 §15.3, M19 §19.1.2–19.2.4; design-specific adaptations are internally designed; M03 §3.2.1–3.2.4; details concerning dose, persistence, and effect modification are internally designed - Related sources: S23 ### N16 · Are the allocation, treatment/assessor blinding, and recurrent-event measurement conditions in the comparison of biotin added to the same lacquer actually verified? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Chiavetta was a randomized add-on trial with open treatment and blinded assessors. Both groups used the same hydroxypropyl chitosan lacquer, and severity of the great toenail was assessed. - Why unverified: The actual background treatment, design and assessment blinding are verified, but this is not a direct comparison of recurrent breakage events. - Reason for missing information: Allocation concealment, actual adherence, event collection and blinding of event-endpoint measurement remain unverified. - Required materials and conditions: Lacquer and biotin composition by arm, allocation, treatment/assessor blinding, and target site - Materials to obtain first: Lacquer and biotin composition by arm, allocation, treatment/assessor blinding, and target site - Further research: Use the same background care and products, and document allocation, measurement and rescue treatment in line with the effect of interest. - Conditions for verification: Preserve the actual randomized add-on design with open treatment and blinded assessors, and check the extent of verification of allocation concealment, actual adherence, recurrent-event collection, and blinding of event measurement. Do not confirm that event-comparison conditions are met solely from a great-toenail severity assessment. - Why this condition is needed: Needed to distinguish the effect of common topical care, the add-on effect of biotin, and measurement blinding. - Application exceptions: Preserve the fact that assessment was assessor-blinded even with open treatment. Adapt the common background treatment to the sole-active add-on condition while retaining the endpoint mismatch. - Remaining uncertainty: Allocation concealment, actual adherence, event collection and blinding of event-endpoint measurement remain unverified. - Referenced methods: M03 §3.2.2–3.2.3; reverse-direction labeling and adaptations for testing are internally designed; M08 §8.1–8.2.3; internal application; M03 §3.2.3, M08 §8.2.2–8.2.3; internal application; M08 Table 8.2.a, M03 §3.2.4; internal application - Related sources: S24 ### N17 · For the 24 participants in the add-on group and 26 in the lacquer group, are the actual denominators for allocation, completion, endpoint-specific analysis and recurrent events verified? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The retained Korean text records a comparison of biotin 10 mg/day added for 24 participants versus lacquer alone for 26 participants over 4 months. Denominators for target-event analysis and completion remain unverified in evidence.n and actual_trial_fields. - Why unverified: The numbers of people compared and the treatment duration are verified, but these are not recurrent-event counts or the actual denominators for endpoint-specific analysis or completion. - Reason for missing information: Arm-specific endpoint-analysis/completion denominators, reasons for withdrawal, event counts and observation time remain unverified. - Required materials and conditions: Arm-specific denominators for allocation, measurement, completion and endpoint analysis, and handling of withdrawals/missing data - Materials to obtain first: Arm-specific denominators for allocation, measurement, completion and endpoint analysis, and handling of withdrawals/missing data - Further research: Report the arm-specific flow of people, nails, events and missing data, and separately plan for the effect of assignment and the effect among completers. - Conditions for verification: Compare the reported 24 and 26 participants with the scope of actual verification of arm-specific denominators for completion, endpoint analysis, recurrent events and observation time. Do not reuse participant counts as event counts or as denominators for every endpoint analysis. - Why this condition is needed: Required to avoid automatically reusing the number of people in a group as the event count or as the denominator for every endpoint analysis. - Application exceptions: Preserve the 24/26 retained in the source, but do not back-calculate integer responder counts from the proportions. - Remaining uncertainty: Arm-specific endpoint-analysis/completion denominators, reasons for withdrawal, event counts and observation time remain unverified. - Referenced methods: M08 Table 8.2.a, M15 §15.3, M19 §19.1.2–19.2.4; design-specific adaptations are internally designed; M08 §8.2.2, M15 §15.3.1; internal application - Related sources: S24 ### N18 · Is Chiavetta's severity reduction of 1.4 versus 0.9 points with P=0.03 a direct recurrent breakage-event result? Verification status: Not met Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Chiavetta's reduction in lamellar-splitting severity was 1.4 points in the add-on group versus 0.9 points in the lacquer group, with a between-group P=0.03. The current source text explicitly states that this value is not event frequency. - Why unverified: The positive figures describe a change in severity and do not answer the selected question about recurrent breakage events. - Reason for missing information: Direct event counts, between-group event differences, CIs and clinical importance remain unverified. - Required materials and conditions: Original severity scale, change/analysis, score difference, CI and separate event results - Materials to obtain first: Original severity scale, change/analysis, score difference, CI and separate event results - Further research: If severity and recurrent events are collected together, distinguish each endpoint in advance and report a separate estimate and interval for each. - Conditions for verification: Compare the original severity definition behind the positive figures with the conditions for direct recurrent events, and preserve the original values. - Why this condition is needed: Required to preserve the positive result without turning it into a reduction in the number of breakages. - Application exceptions: Preserve the nominal between-group P value, but do not calculate a CI, a new difference, an effect size or clinical importance. - Remaining uncertainty: Direct event counts, between-group event differences, CIs and clinical importance remain unverified. - Referenced methods: M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M04 §4.6.3, M15 §15.3.1–15.3.3; separation of statuses is internally designed; M15 §15.3.1–15.3.3; internal application; M03 §3.2.4; internally defined extension boundary - Related sources: S24 ### N19 · Do the different OGSS responder proportions meet the conditions for direct recurrent breakage events? Verification status: Not met Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: OGSS improvement of at least 50% was seen in 80% of the add-on group versus 53% of the lacquer group, P=0.05. Improvement of at least 1 point was 91% versus 73%, P=0.2. Each proportion is a responder measure, not a breakage-event rate. - Why unverified: The two response criteria differ from the selected recurrent-event-count conditions. The difference in nominal P values does not warrant a Conflicting information status or imply equivalence. - Reason for missing information: Actual responder denominators for each criterion, multiple comparisons, CIs and direct event results remain unverified. - Required materials and conditions: Each threshold, responder denominator, analysis, time point, multiple-comparison plan and interval - Materials to obtain first: Each threshold, responder denominator, analysis, time point, multiple-comparison plan and interval - Further research: Prespecify the original response criteria and multiple-comparison plan, and analyze recurrent events as a separate endpoint. - Conditions for verification: Preserve 80%/53% with P=.05 and 91%/73% with P=.2 under their respective original criteria, and assess whether they match the conditions for direct recurrent events. - Why this condition is needed: Required to avoid conflating proportions of people who improved and their thresholds with recurrent events or equivalence. - Application exceptions: Improvement of at least 50% and of at least 1 point are different definitions. Do not interpret a nonsignificant finding as equivalence or an effect of 0. - Remaining uncertainty: Actual responder denominators for each criterion, multiple comparisons, CIs and direct event results remain unverified. - Referenced methods: M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M04 §4.6.3, M15 §15.3.1–15.3.3; separation of statuses is internally designed; M08 §8.2.2, M15 §15.3.1; internal application; M15 §15.3.1–15.3.3; internal application - Related sources: S24 ### N20 · Has Shemer's retrospective comparison been documented with the current scope of reading and with direct event results remaining unverified? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The Shemer 2025 record documents a retrospective comparison and complete/partial response categories identified in indexed fragments. The historical 403 response from the journal full text and empty response from native PubMed left the dose, arm denominators and standardized event collection unverified. Figures from commercial retellings were not adopted. - Why unverified: The retained inputs do not contain the full-text coverage needed to verify actual direct event counts, comparisons and methods. - Reason for missing information: Exact dose, denominators, event diary, standardized observation period and direct between-group effect remain unverified. - Required materials and conditions: Product, dose, arm denominators, event collection and analysis in the original full text, and actual scope of access - Materials to obtain first: Product, dose, arm denominators, event collection and analysis in the original full text, and actual scope of access - Further research: If the full text is obtained, examine the actual comparison, ingredients and event definition, and assess limitations from retrospective selection/recall. - Conditions for verification: Link the indexed retrospective response categories with the fact that direct event results remain unverified. - Why this condition is needed: Required to avoid promoting indexed response categories to verified breakage events or full-text results. - Application exceptions: The historical journal 403 and empty PubMed response are not new access failures in the current review, nor do they mean study absence or negative results. - Remaining uncertainty: Exact dose, denominators, event diary, standardized observation period and direct between-group effect remain unverified. - Referenced methods: M04 §4.5–4.6 principles for data collection/selection; separation of access from reading and the hyperlink contract are internally designed; M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M08 Table 8.2.a, M15 §15.3, M19 §19.1.2–19.2.4; design-specific adaptations are internally designed; M08 §8.1–8.2.3; internal application - Related sources: S25 ### N21 · Does Patel's Sesbania extract isolate the effect of biotin alone on recurrent breakage events? Verification status: Not met Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Patel's biotin-labeled arm uses a Sesbania extract product. The Korean text for the current 3104 explicitly states that a single-active-ingredient effect cannot be isolated, and does not directly provide exact product content or dosing frequency. - Why unverified: The intervention currently verified does not meet the selected conditions for a direct effect of biotin as the sole active ingredient. - Reason for missing information: Product amount, purity, the contribution of biotin alone and a regimen eligible for the event question remain unverified and are absent from the current inputs. - Required materials and conditions: Complete product composition, active ingredients, biotin content and additional ingredients in each arm - Materials to obtain first: Complete product composition, active ingredients, biotin content and additional ingredients in each arm - Further research: Directly estimate the ingredient's contribution through a comparison that distinguishes biotin as the sole active ingredient from a control with the same background care. - Conditions for verification: Compare the actual product ingredients and endpoints with the conditions for biotin alone and recurrent events, and use only a contribution that can be isolated as a direct effect. - Why this condition is needed: Required to avoid wrongly attributing contributions from the extract's other ingredients to biotin alone. - Application exceptions: A product described as biotin is different from isolated biotin. Do not import specific product amounts or doses from an adjacent manuscript when those values are absent from the current inputs. - Remaining uncertainty: Product amount, purity, the contribution of biotin alone and a regimen eligible for the event question remain unverified and are absent from the current inputs. - Referenced methods: M03 §3.2.2–3.2.3; reverse-direction marking and test adaptations are internally designed; M03 §3.2.3, M08 §8.2.2–8.2.3; internal application - Related sources: S05 ### N22 · Does the primary/secondary endpoint hierarchy for Patel's nail PGA agree across Methods, Results and the registry? Verification status: Conflicting information Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Patel's 0–5-point nail PGA measures peeling, brittleness and surface severity. The current source records conflicting primary/secondary labels for nails in Methods/Results and states that the registry history and analysis plan could not be verified. - Why unverified: This is a discrepancy in the explicitly stated endpoint hierarchy within the same report, not simply a difference between figures from different analyses. Separately, it does not qualify as a direct event result. - Reason for missing information: Corrections to the conflict, reasons for hierarchy changes, registry history/SAP and recurrent-event results remain unverified. - Required materials and conditions: Original Methods/Results, registry/protocol/SAP, explanation of hierarchy changes and corrections - Materials to obtain first: Original Methods/Results, registry/protocol/SAP, explanation of hierarchy changes and corrections - Further research: Prespecify measurement, endpoint hierarchy and analysis order, and disclose the reasons for changes if the registry and source text disagree. - Conditions for verification: Compare the PGA 0–5 definition and agreement/disagreement in the Methods/Results primary/secondary hierarchy, and distinguish registry/SAP material that has not been obtained from corrections. - Why this condition is needed: Required to avoid converting severity PGA to event frequency or arbitrarily correcting the hierarchy conflict in the source text. - Application exceptions: Preserve the discrepancy in the hierarchy of the same endpoint between Methods/Results, but do not conclude that selective reporting is established. Do not mark the original PDF containing the conflict as having been read on this occasion. - Remaining uncertainty: Corrections to the conflict, reasons for hierarchy changes, registry history/SAP and recurrent-event results remain unverified. - Referenced methods: M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M04 §4.6.3, M15 §15.3.1–15.3.3; separation of statuses is internally designed; M08 Table 8.2.a, M03 §3.2.4; internal application; M08 Table 8.2.a, M04 §4.6.3; internal application - Related sources: S05, S31 ### N23 · Were the statement "withdrawals excluded" and the actual denominators for allocation, completion and analysis distinguished? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Patel's retained English design description records "randomized double-blind placebo-controlled" and "withdrawals excluded." The citation refers to historical verification of flowchart/analysis-population locations, but does not provide actual participant counts in this retained summary. - Why unverified: The statement that withdrawals were excluded is verified, but actual arm-specific and endpoint-specific denominators and the impact of exclusions remain unverified. - Reason for missing information: Allocation and completion counts, PGA analysis n, withdrawal reasons, ITT/PP, missing-data handling and event denominators remain unverified. - Required materials and conditions: Participant flow by arm, reasons for withdrawal, analysis population and PGA analysis denominators - Materials to obtain first: Participant flow by arm, reasons for withdrawal, analysis population and PGA analysis denominators - Further research: Report the flow through allocation, measurement, withdrawal and analysis for each endpoint, and prespecify a plan for sensitivity analyses of missing data. - Conditions for verification: Distinguish the actual statement "withdrawals excluded" from unverified denominators and the scope of handling. - Why this condition is needed: Required to avoid supplementing the statement that withdrawals were excluded with an assumed ITT analysis or arbitrary completer counts. - Application exceptions: Do not import allocation or completion counts from other manuscripts that are absent from the current inputs. Verify allocation, completion and endpoint analysis separately. - Remaining uncertainty: Allocation and completion counts, PGA analysis n, withdrawal reasons, ITT/PP, missing-data handling and event denominators remain unverified. - Referenced methods: M08 Table 8.2.a, M15 §15.3, M19 §19.1.2–19.2.4; design-specific adaptations are internally designed; M08 §8.2.2, M15 §15.3.1; internal application - Related sources: S05 ### N24 · For S05 and NCT05972512 in the same F06 family, is material verified that permits comparison of the actual registered endpoint hierarchy, change history and SAP with the paper? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: F06 in the retained evidence links S05 and S31. The paper reports NCT05972512 and CTRI/2023/11/055359, but only a shell of the actual registry page was obtained historically, leaving the hierarchy, changes and SAP unverified. - Why unverified: The relationship identifying the same family is verified, but there is no independent verification of the registry plan, history or results. - Reason for missing information: Actual registry text, change history, analysis plan and comparison of plans/results remain unverified. - Required materials and conditions: Same-trial identifiers, registry history, protocol, SAP and comparison with the paper's results - Materials to obtain first: Same-trial identifiers, registry history, protocol, SAP and comparison with the paper's results - Further research: After linking trial identities, compare the original plan with actual endpoints, time points and analyses, and document the reasons for changes. - Conditions for verification: Preserve the same-family relationship between S05 and S31, and compare the identifiers reported in the paper with the scope of the registry plan, change history and SAP actually obtained. Do not promote a registry shell to verification of the full plan. - Why this condition is needed: Required to avoid counting the paper and registry record as two independent replication trials. - Application exceptions: The fact that NCT/CTRI identifiers are reported in the paper is distinct from verification of the actual registry history, timing and plan. - Remaining uncertainty: Actual registry text, change history, analysis plan and comparison of plans/results remain unverified. - Referenced methods: M04 §4.6.1–4.6.2 distinction between studies and reports; cohort/outcome linkage is an internal application; M04 §4.5, §4.6.3; constraints on the current data conversion reflect the user-defined scope and internal design; M08 Table 8.2.a, M04 §4.6.3; internal application - Related sources: S05, S31 ### N25 · Do Hexsel's before-and-after collagen data provide controlled effects of biotin alone on recurrent breakage events? Verification status: Not met Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Hexsel 2017 provides uncontrolled, open-label before-and-after data on specific bioactive collagen peptides. Even though broken-nail frequency is mentioned, the substance is collagen and this is not a between-group effect of biotin. - Why unverified: The actual active substance and contrast do not match the selected between-group question about biotin alone. - Reason for missing information: These data do not provide direct recurrent-event results, a control comparison or intervals for biotin. - Required materials and conditions: Original text on the actual active substance, control, breakage collection and before-and-after versus between-group analyses - Materials to obtain first: Original text on the actual active substance, control, breakage collection and before-and-after versus between-group analyses - Further research: Even when using methods for collecting breakage frequency as a reference, separately design the control comparison for biotin alone and fix the substance identity. - Conditions for verification: Compare the actual substance, contrast and endpoint with the controlled event conditions for biotin alone, and retain measurement data from another molecule in a separate role. - Why this condition is needed: Required to avoid importing the effect of a different molecule merely because the endpoint wording is similar. - Application exceptions: Event measurements in studies of other molecules can be retained as pointers for future design, but are not evidence of biotin's effects. - Remaining uncertainty: These data do not provide direct recurrent-event results, a control comparison or intervals for biotin. - Referenced methods: M03 §3.2.2–3.2.3; reverse-direction marking and test adaptations are internally designed; M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M08 §8.1–8.2.3; internal application; M08 §8.2.2, M15 §15.3.1; internal application - Related sources: S26 ### N26 · Have the PGA wording in the registry shell and the unverified composition and event results been distinguished? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: NCT05800496 is limited to registry discovery, a page shell and indexed PGA wording. Product composition, protocol, status and results were not verified in the retained review. - Why unverified: Registry identity clues alone cannot establish the selected between-group results for biotin alone and recurrent breakage. - Reason for missing information: Product composition, event definition, actual denominators, status and plans/results remain unverified. - Required materials and conditions: Original registry text, composition, actual population/endpoints, status, results and change history - Materials to obtain first: Original registry text, composition, actual population/endpoints, status, results and change history - Further research: If the registry and protocol are obtained, first compare the substance, endpoint, observation window and result identities, then reassess eligibility. - Conditions for verification: Separate shell/indexed PGA clues from unverified event results. - Why this condition is needed: Required to avoid overstating the existence of a registry number as acquisition of eligible-product information and trial results. - Application exceptions: Do not turn historical API access failure into a current retrieval failure, negative results, termination or 0 participants. - Remaining uncertainty: Product composition, event definition, actual denominators, status and plans/results remain unverified. - Referenced methods: M04 §4.6.1–4.6.2 distinction between studies and reports; cohort/outcome linkage is an internal application; M04 §4.5–4.6 principles for data collection/selection; separation of access from reading and the hyperlink contract are internally designed; M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M04 §4.5, §4.6.3; constraints on the current data conversion reflect the user-defined scope and internal design; M08 Table 8.2.a, M04 §4.6.3; internal application - Related sources: S29 ### N27 · Did the review avoid inferring timing, composition or results from the registry number and title? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: NCT07373574 is a search/registry identity clue for Effects of Dietary Supplements on Nail and Hair Health. The currently retained source text leaves status, timing, composition and results unverified and did not infer dates from the number. - Why unverified: There is no registry text available to verify the actual product and direct recurrent-breakage results. - Reason for missing information: Registry timing, status, product, event definition, denominators and results remain unverified. - Required materials and conditions: Actual registry text, initiation/changes, composition, endpoints, results and identifiers - Materials to obtain first: Actual registry text, initiation/changes, composition, endpoints, results and identifiers - Further research: After obtaining the formal original registry text, assess agreement in timing, intervention, population and endpoints, and preserve the change history. - Conditions for verification: Distinguish the currently verified shell/indexed metadata from what remains unverified by source location. - Why this condition is needed: Required to avoid inventing current trial status or breakage results from search clues. - Application exceptions: Do not infer dates, recruitment or completion status from the order of registry numbers. A nail/hair title is not a direct event definition. - Remaining uncertainty: Registry timing, status, product, event definition, denominators and results remain unverified. - Referenced methods: M04 §4.6.1–4.6.2 distinction between studies and reports; cohort/outcome linkage is an internal application; M04 §4.5–4.6 principles for data collection/selection; separation of access from reading and the hyperlink contract are internally designed; M04 §4.5, §4.6.3; constraints on the current data conversion reflect the user-defined scope and internal design; M08 Table 8.2.a, M04 §4.6.3; internal application - Related sources: S30 ### N28 · Have the discovery and diagnostic context provided by reviews been distinguished from unique direct trials? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: S22 reused the review extract from the historical 866 record. S27 is a record of review full-text access for diagnostic and treatment discovery context; S28 is limited to the indexed abstract/list for the 2024 online publication/2025 issue. The three reviews are not independent direct trials. - Why unverified: The current bibliographic information can be distinguished from historical roles and access levels, but no up-to-date exhaustive review search or reverification of original-trial events was performed. - Reason for missing information: Direct event results from included trials, search comprehensiveness and complete full-text coverage of some reviews remain unverified. - Required materials and conditions: Review full text, included references, search cutoff date, diagnostic context and links to original trials - Materials to obtain first: Review full text, included references, search cutoff date, diagnostic context and links to original trials - Further research: Link the original trial families of the included references, examine direct-event eligibility individually and do not substitute an average from a review. - Conditions for verification: Attribute the roles and access levels of Lipner/Scher, Chessa and Zaraa/Richert to their respective materials. - Why this condition is needed: Required to avoid using a review as evidence of a new randomized replication trial or an up-to-date exhaustive search. - Application exceptions: Preserve older reviews and indexed metadata while distinguishing included trials, citation context and the actual reading scope. - Remaining uncertainty: Direct event results from included trials, search comprehensiveness and complete full-text coverage of some reviews remain unverified. - Referenced methods: M04 §4.6.1–4.6.2 distinction between studies and reports; cohort/outcome linkage is an internal application; M04 §4.5–4.6 principles for data collection/selection; separation of access from reading and the hyperlink contract are internally designed; M03 §3.2.1; detailed population conditions are internally designed; M04 §4.5, §4.6.3; constraints on the current data conversion reflect the user-defined scope and internal design - Related sources: S22, S27, S28 ### N29 · Has overlap among same-family reports, repeated citations and previous broad nail verdicts been managed? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The current evidence records F01–F09, and S05/S31 belong to F06. 866 is a broad verdict on thickness, surface, subjective hardness, splitting and overall severity, and is not an exact duplicate of the new breakage-frequency question. Preserve the existing D grade and 28 points only as a historical description in the original source. - Why unverified: The retained families and differences from the previous question are verified, but the final number of independent direct trials cannot be established without separate family/audit files. - Reason for missing information: Complete linkage of original participants, overlapping cohorts and other reports, and the final count of unique direct trials remain unverified. - Required materials and conditions: Report-to-trial families, the same results/time points, boundaries of earlier verdicts and actual overlap identities - Materials to obtain first: Report-to-trial families, the same results/time points, boundaries of earlier verdicts and actual overlap identities - Further research: Link papers, registry records and reviews at the trial level, verify overlap in the original participants and results, then describe independent comparisons. - Conditions for verification: Preserve the current evidence families and the S05/S31 link; do not revise or carry forward the different endpoints or original grade of 866. - Why this condition is needed: Required to avoid importing report counts and past grades as independent evidence for the new question. - Application exceptions: F01–F09 are structural family IDs in the current source. Without a separate family table verifying actual overlap, do not establish the final count of unique trials. - Remaining uncertainty: Complete linkage of original participants, overlapping cohorts and other reports, and the final count of unique direct trials remain unverified. - Referenced methods: M03 §3.1, §3.2.1–3.2.4 principles for clarifying the question; detailed separation rules are internally designed; M04 §4.6.1–4.6.2 distinction between studies and reports; cohort/outcome linkage is an internal application; M04 §4.6.3, M15 §15.3.1–15.3.3; separation of statuses is internally designed - Related sources: S05, S31, S20, S21, S23, S24, S25, S26, S29, S30 ### N30 · Have allocation and treatment/assessment blinding been reviewed in relation to the actual endpoint concerned? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Chiavetta is retained as an open-treatment/assessor-blinded design, and Patel as a double-blind, placebo-controlled extract design. However, direct event measurement, baseline balance and allocation concealment were not verified. - Why unverified: Although the design of the related material is known, the data needed to actually assess bias in the selected direct event result are unavailable. - Reason for missing information: Eligible allocation, baseline balance, concealment and between-arm differences in event measurement remain unverified. - Required materials and conditions: Allocation/concealment, baseline characteristics, event measurement by arm and assessor blinding/verification - Materials to obtain first: Allocation/concealment, baseline characteristics, event measurement by arm and assessor blinding/verification - Further research: Document allocation, baseline and measurement procedures, and apply the same event collection and assessment verification in both groups. - Conditions for verification: Separate the actual severity-assessment design from the unverified measurement of eligible recurrent events. - Why this condition is needed: Required to avoid claiming that recurrent-event measurement/confounding issues are resolved solely from RCT and blinding labels. - Application exceptions: Do not treat inability to blind as automatic failure. Open treatment and blinded assessors can coexist within the same material. - Remaining uncertainty: Eligible allocation, baseline balance, concealment and between-arm differences in event measurement remain unverified. - Referenced methods: M08 §8.1–8.2.3; internal application; M08 Table 8.2.a, M03 §3.2.4; internal application; M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed - Related sources: S24, S05 ### N31 · Are shared care, concurrent exposure, adherence and rescue treatment actually verified for each arm? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Chiavetta's use of the same lacquer is verified, but the actual background_care, rescue_care, adherence and concurrent_supplements for the eligible recurrent-event comparison are all null. - Why unverified: Identifying the shared lacquer alone does not meet the full conditions for concomitant treatment, adherence and rescue care in the actual event comparison. - Reason for missing information: Actual treatment continuation, adherence, changes, rescue care and between-arm differences in care remain unverified. - Required materials and conditions: Nail care, concurrent products, actual adherence, changes, rescue care and handling in analysis by arm - Materials to obtain first: Nail care, concurrent products, actual adherence, changes, rescue care and handling in analysis by arm - Further research: Prospectively collect data on care, concurrent supplementation, rescue treatment and adherence, and handle them using an analysis aligned with the effect of interest. - Conditions for verification: Document use of the same lacquer separately from unverified concomitant treatment and adherence in the actual eligible event comparison. - Why this condition is needed: Required to avoid attributing differences in concurrent care or adherence to biotin itself. - Application exceptions: Do not require all changes in both groups to be identical. Distinguish the actual effect of assignment/effect of adherence and the scope of handling. - Remaining uncertainty: Actual treatment continuation, adherence, changes, rescue care and between-arm differences in care remain unverified. - Referenced methods: M03 §3.2.2–3.2.3; reverse-direction marking and test adaptations are internally designed; M03 §3.2.3, M08 §8.2.2–8.2.3; internal application - Related sources: S24 ### N32 · Are missing data, completer analysis and clustered/recurrent structures linked to the actual effect of interest? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Floersheim reports 71 treated participants with 45 evaluated, and Patel states "withdrawals excluded," but the analysis population, missing-data handling and model for within-person recurrent-event/nail correlations for eligible event results were not verified. - Why unverified: Some evaluation/withdrawal descriptions are available, but they cannot be linked to the selected direct event estimate and the impact of omissions. - Reason for missing information: ITT/PP, missing data, adjustment, recurrent/clustered models and effects of discontinuing observation remain unverified. - Required materials and conditions: Endpoint-specific analysis populations, reasons for missing data/withdrawal, within-participant correlations, adjustment and model/SAP - Materials to obtain first: Endpoint-specific analysis populations, reasons for missing data/withdrawal, within-participant correlations, adjustment and model/SAP - Further research: Prespecify the flow of allocation, completion and analysis and within-person recurrent-event/nail correlations, and plan sensitivity analyses for missing data. - Conditions for verification: Distinguish the currently described scope of withdrawal/evaluation from gaps in eligible direct event analysis. - Why this condition is needed: Required to avoid producing precision estimates that ignore correlations involving people, nails and recurrent events, or selective evaluation. - Application exceptions: Preserve the limitations of Floersheim's evaluable participants and Patel's exclusion of withdrawals. Do not fill unreported analyses with ITT, PP or complete follow-up. - Remaining uncertainty: ITT/PP, missing data, adjustment, recurrent/clustered models and effects of discontinuing observation remain unverified. - Referenced methods: M08 Table 8.2.a, M15 §15.3, M19 §19.1.2–19.2.4; design-specific adaptations are internally designed; M08 §8.2.2, M15 §15.3.1; internal application - Related sources: S23, S05 ### N33 · Have the direct between-group breakage-event effect, CI and important difference been reported? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Eligible between_group_effect, CI, P and MCID are all null. Chiavetta's nominal P values for severity/OGSS are retained but do not provide intervals for the event effect. - Why unverified: No values or criteria are available to interpret the selected direct event estimate or its clinical importance. - Reason for missing information: Direct between-group event-count differences, CIs, variance and important differences remain unverified. - Required materials and conditions: Direct between-group event-count estimate, units, denominators, CI, variance and a justified important difference - Materials to obtain first: Direct between-group event-count estimate, units, denominators, CI, variance and a justified important difference - Further research: Plan precision in line with the event distribution, recurrent structure and justified important difference, and report the actual intervals. - Conditions for verification: Distinguish null values for the direct effect, CI, P and MCID from nominal P values for other endpoints. - Why this condition is needed: Required to avoid substituting trial count, sample size or nominal P values for the precision or importance of the direct effect. - Application exceptions: If the clinically important difference remains undetermined, retain that status. Do not create a common minimum sample, duration or number of studies, even as proposed numbers. - Remaining uncertainty: Direct between-group event-count differences, CIs, variance and important differences remain unverified. - Referenced methods: M03 §3.2.4, M15 §15.3.1–15.3.3; question-specific outcome adaptations are internally designed; M08 Table 8.2.a, M15 §15.3, M19 §19.1.2–19.2.4; design-specific adaptations are internally designed; M15 §15.3.1–15.3.3; internal application - Related sources: S24 ### N34 · Can prespecified event endpoints, time points and analyses be compared with actual reporting? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Patel's actual registration history and SAP are unverified, and the historical records also show that the full registry contents for S29/S30 were not acquired. The current input contains no material with which to compare eligible recurrent-event plans and reports. - Why unverified: There is no material with which to complete a comparison of the formal prespecified event plan with the results. Nonregistration or selective reporting is not established. - Reason for missing information: Eligible protocols, SAPs, multiple comparisons/changes, and the current status of corrections/retractions are unverified. - Required materials and conditions: Protocol, registry history, SAP, corrections, actual event results and reasons for changes - Materials to obtain first: Protocol, registry history, SAP, corrections, actual event results and reasons for changes - Further research: Preregister the event definition, window, effect of interest, and multiple comparisons, and report the reasons for changes and all planned outcomes. - Conditions for verification: Distinguish the scope in which plans and reports have been compared from the event questions for which they have not yet been compared. - Why this condition is needed: Required to avoid treating registry material that has not been obtained as confirmation of nonregistration or selective reporting. - Application exceptions: Preserve the Patel hierarchy conflict separately. Do not automatically classify unverified plans in other studies as the same conflict. - Remaining uncertainty: Eligible protocols, SAPs, multiple comparisons/changes, and the current status of corrections/retractions are unverified. - Referenced methods: M04 §4.5, §4.6.3; limits on the current material conversion follow the user's scope and are internally designed; M08 Table 8.2.a, M04 §4.6.3; internal application - Related sources: S31, S29, S30, S05 ### N35 · Are product provision, funding, and authors' competing interests verified through the actual disclosure wording? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Each evidence.funding field refers to separate trial_families/evidence_appraisal material. S05 records the product/COI location at pp1–4, and S24 records the funding/conflict location at p4, but this retained summary contains no detailed disclosures or company names. Independence has not been verified. - Why unverified: Only references and locations of sections read historically are present; the current input contains no actual funding/product provision/employment disclosure wording. - Reason for missing information: Study-specific funding details, product provision, employment/patents, analytical independence, and independence between study families are unverified. - Required materials and conditions: Actual wording on disclosed COI, research funding, product provision, author employment/patents, and institutions/study families - Materials to obtain first: Actual wording on disclosed COI, research funding, product provision, author employment/patents, and institutions/study families - Further research: Disclose product provision, funding sources, analysts' roles, and declarations, and actually verify whether replications share funding/study families. - Conditions for verification: Distinguish the clues to original COI locations in the current 3104 record from the unverified funding details. - Why this condition is needed: Needed to prevent historical identification of a COI location or a referenced filename from being treated as proof of independent funding or independent replication. - Application exceptions: Do not automatically exclude a study because of corporate relationships, or judge it independent or free from bias because disclosure wording is absent. Do not infer company names or employment facts absent from the current material. - Remaining uncertainty: Study-specific funding details, product provision, employment/patents, analytical independence, and independence between study families are unverified. - Referenced methods: Chamgap's own independence and attribution conditions. The official method sections used in this demonstration do not validate all of these detailed items; the distinction between studies and reports in M04 §4.6.1–4.6.2; linking cohorts/outcomes is an internal application - Related sources: S20, S21, S23, S24, S25, S05, S26, S29, S30 ### N36 · Are the actual adverse events, discontinuations, and data-collection denominators for this use verified? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The original safety status is Caution. The current source explicitly states that adverse events and discontinuations by arm, and long-term safety/safety in vulnerable groups for use in brittle nails, are unverified. - Why unverified: There is no direct information on harm collection, denominators, or discontinuations for this use. - Reason for missing information: Exposure by arm, people with adverse events/event counts, follow-up/discontinuations, and systematic collection are unverified. - Required materials and conditions: Adverse-event definitions, collection methods, exposure/events by arm, discontinuations, and loss to follow-up - Materials to obtain first: Adverse-event definitions, collection methods, exposure/events by arm, discontinuations, and loss to follow-up - Further research: Plan systematic adverse-event collection, discontinuation assessment, and follow-up for the same exposure/population, and report denominators and duration by arm. - Conditions for verification: Separate the verified safety context from the unverified harms by arm for this use. - Why this condition is needed: Needed to prevent safety from being regarded as verified merely because efficacy data exist or harms are unreported. - Application exceptions: Separate recurrent breakage events used to assess efficacy from adverse events. Do not remove other prior efficacy outcomes because harms were unreported. - Remaining uncertainty: Exposure by arm, people with adverse events/event counts, follow-up/discontinuations, and systematic collection are unverified. - Referenced methods: M19 §19.1.2–19.2.4; internal application; M19 §19.1.2–19.2.4; detailed distinctions are internally designed; M19 §19.1.2–19.2.4, M04 §4.6.3; internal application; M08 Table 8.2.a, M15 §15.3, M19 §19.1.2–19.2.4; design-specific adaptations are internally designed - Related sources: S06, S07 ### N37 · Are the actual populations, exposures, timing, and assay-specific scope of applicability of interference with thyroid, NT-proBNP, and troponin tests verified? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The inherited NIH wording describes interference with some thyroid assays after a single 10 mg dose (within 24 hours), and with some TSH/NT-proBNP assays in 6 healthy people exposed to 10 mg/day for 1 week. The FDA warns of falsely low results in some troponin assays. - Why unverified: The assay-specific exposure and denominator signals in the historical manuscript have been preserved, but this is neither current reverification of external original texts nor general risk estimation. - Reason for missing information: Platform-specific risk rates, an identical stopping interval for all assays, and the scope of assay applicability to this use are unverified. - Required materials and conditions: Original assay methods, doses/timing, healthy-participant denominators, collection, official restatements, and limitations - Materials to obtain first: Original assay methods, doses/timing, healthy-participant denominators, collection, official restatements, and limitations - Further research: Verify the scope of interference through assay-specific validation that records applicability conditions such as the assay platform, exposure/blood-sampling times, and renal function. - Conditions for verification: Preserve the single/repeated doses, timing, populations, and specific assay signals in the historical material, and compare the scope of verified original material with what is needed for applicability by assay, reagent, and population and for general risk estimation. Do not treat inherited summaries as current reverification of external full texts or as universal risk rates. - Why this condition is needed: Needed to prevent assay-dependent interference from being generalized to an identical risk rate or stopping interval for all tests and people. - Application exceptions: Official restatements do not constitute independent case counts. Short-term exposure in healthy people does not answer the question of long-term safety in brittle nails. - Remaining uncertainty: Platform-specific risk rates, an identical stopping interval for all assays, and the scope of assay applicability to this use are unverified. - Referenced methods: M19 §19.1.2–19.2.4; internal application; M19 §19.1.2–19.2.4; detailed distinctions are internally designed; design-specific harm questions in M19 §19.2; temporal-relationship details are internally designed; M19 §19.2.2–19.2.4, M03 §3.2.3; internal application; Chamgap's own interpretation boundaries. M19 principles are referenced; no official causality tool was applied - Related sources: S06, S07 ### N38 · Are there actual exposure, event, and follow-up data to verify long-term safety and safety during pregnancy/lactation, in children, and in liver or kidney disease for this use? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The original text explicitly states that adequate intake is not a therapeutic dose for brittle nails and that the absence of an established UL does not mean unlimited safety. Long-term safety and safety during pregnancy and lactation, in children, and in liver or kidney disease for this use are unverified. - Why unverified: There is no direct denominator/follow-up information to verify safety in broader populations or over the long term. - Reason for missing information: Long-term and rare harms, exposure/events in each vulnerable group, interactions, and continued follow-up are unverified. - Required materials and conditions: Actual exposure by population, long-term/rare harms, interactions, and original nutritional standards - Materials to obtain first: Actual exposure by population, long-term/rare harms, interactions, and original nutritional standards - Further research: Investigate long-term harms and harms in vulnerable groups through actual use and systematic follow-up by population, and separate nutritional standards from treatment questions. - Conditions for verification: Assess whether actual exposure, event denominators, and long-term follow-up by population answer the questions underlying extended safety claims. Do not use adequate intake or the absence of an established UL as evidence for a therapeutic dose, an optimal dose, or unlimited safety. - Why this condition is needed: Needed to prevent adequate intake and the absence of an established upper limit from being treated as a therapeutic dose or unlimited safety. - Application exceptions: Not every rare-harm study is required for the current narrow event-efficacy question, but broader safety remains separately unverified. - Remaining uncertainty: Long-term and rare harms, exposure/events in each vulnerable group, interactions, and continued follow-up are unverified. - Referenced methods: M19 §19.1.2–19.2.4; internal application; Chamgap's own interpretation boundaries. M19 principles are referenced; no official causality tool was applied; M03 §3.2.1; detailed population conditions are internally designed - Related sources: S06, S07 ### N39 · Is there direct material supporting extensions to optimal dose, persistence after discontinuation, or effects by anatomical site? Verification status: Unverified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: Hardness responses to 2.5 mg/day over variable durations and great-toenail severity with 10 mg/day over 4 months do not constitute a direct dose comparison. Site-specific event effects, persistence after discontinuation, and the optimal dose have not been verified. - Why unverified: The current material contains no direct dose, follow-up, or interaction estimates that answer these extensions of the breakage-event question. - Reason for missing information: Optimal dose, effects during maintenance/after discontinuation, and effect modification by anatomical site are unverified. - Required materials and conditions: Direct dose comparisons, follow-up after discontinuation/over the long term, anatomical-site strata, and prespecified interactions - Materials to obtain first: Direct dose comparisons, follow-up after discontinuation/over the long term, anatomical-site strata, and prespecified interactions - Further research: When extension questions are actually needed, design separate comparisons with prespecified hypotheses on dose, follow-up after discontinuation, and anatomical site. - Conditions for verification: Distinguish the unverified main effect from the separate lack of direct verification for extensions to dose, persistence, or anatomical site. - Why this condition is needed: Needed to prevent short-term or variable-duration treatment data on other endpoints from being treated as evidence for an optimal regimen or persistent effects. - Application exceptions: Do not require every extension study for the narrow assessment target. Retain each as a separate research question and gap. - Remaining uncertainty: Optimal dose, effects during maintenance/after discontinuation, and effect modification by anatomical site are unverified. - Referenced methods: M03 §3.2.1–3.2.4; dose, persistence, and effect-modification details are internally designed; M03 §3.2.1; detailed population conditions are internally designed; M03 §3.2.2–3.2.3; reverse-direction labeling and assay adaptations are internally designed - Related sources: S23, S24 ### N40 · Has the actual reading of local retained summaries in this review been separated from historical external access, failures, and inherited material? Verification status: Met Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The complete Korean, English, structured, and bibliographic summaries in the current source were actually read. Historical author HTML access/failed PDF download for S24, historical limitations for S25/S29/S30, and inherited-material labels for S06/S07 are historical records. Access to all external materials was unattempted and none were read in this review. - Why unverified: Record current local reading separately from the original source access_level/location and review date, without claiming successful external access. - Reason for missing information: Current external existence, public availability, acquisition, and full-text reading, as well as individual access dates absent from the source, are unverified. - Required materials and conditions: Each material's identity, actual material type, URL, existence/public availability/access/acquisition/reading, and original location/date - Materials to obtain first: Each material's identity, actual material type, URL, existence/public availability/access/acquisition/reading, and original location/date - Further research: When original material is actually acquired, record the timing, safe URL, material type, and content location separately, and preserve the historical original text. - Conditions for verification: Mark the preserved retained summaries as read in this review, and separately mark external materials as access not attempted, not acquired, and Not read. - Why this condition is needed: Needed to prevent bibliographic information, URLs, or historical full-text records from being treated as acquisition or reading of original material in this review. - Application exceptions: No attempt at external access is different from failure. If the actual access date is absent from the source, leave it null and separate it from the original review date of 2026-09-15. - Remaining uncertainty: Current external existence, public availability, acquisition, and full-text reading, as well as individual access dates absent from the source, are unverified. - Referenced methods: Material collection/selection principles in M04 §4.5–4.6; the separation of access from reading and the hyperlink contract are internally designed; M04 §4.5, §4.6.3; limits on the current material conversion follow the user's scope and are internally designed - Related sources: S05, S06, S07, S20, S21, S22, S23, S24, S25, S26, S27, S28, S29, S30, S31 ### N41 · Have the original ?/null, B/P, document quality, and the scope of unverified direct evidence been preserved? Verification status: Met Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The original grade is ?, score is null, and safety is Caution. The subsequent axes after the B/P question classification are null, and related_human_studies_exist=true. The scope of no_human_study is this sole-active-ingredient, controlled recurrent-event question. document_quality A and single-assistant self-review are neither efficacy findings nor external clinical certification. - Why unverified: The original verdict, classification, and limitation metadata were preserved as a conversion record; no new effect, grade, or clinical certification was created. - Reason for missing information: Direct effects, the count of unique direct trials, worldwide absence, and a new official reassessment were not verified. - Required materials and conditions: Original verdict/axes, scope of absence, related human material, document quality, and self-review metadata - Materials to obtain first: Original verdict/axes, scope of absence, related human material, document quality, and self-review metadata - Further research: When new direct material is actually received, review an update to the original verdict and a change to the table's condition version as separate events, without automatic rescoring. - Conditions for verification: Preserve grade ?, score null, B/P, subsequent axes null, bounded scope, and document quality A unchanged. - Why this condition is needed: Needed to prevent bounded stage0 from being treated as an effect of 0, an absence of human studies, or a new score. - Application exceptions: human_study_exists=false/no_human_study=true refers to eligible direct results for the fixed question and is compatible with related_human_studies_exist=true. - Remaining uncertainty: Direct effects, the count of unique direct trials, worldwide absence, and a new official reassessment were not verified. - Referenced methods: Question-clarification principles in M03 §3.1, §3.2.1–3.2.4; detailed separation rules are internally designed; M04 §4.6.3, M15 §15.3.1–15.3.3; status separation is internally designed; M04 §4.5, §4.6.3; limits on the current material conversion follow the user's scope and are internally designed; M03 §3.2.4; internally defined extension boundaries - Related sources: ### N42 · To what extent have follow-up material, corrections/retractions, and public release status actually been verified in relation to the original revision policy and the current authoring history? Verification status: Partly verified Reading scope: Summary read: the current local retained-summary location was read. For the corresponding external material, access was not attempted, and it was neither acquired nor read in this review. - Current findings: The original text records new eligible studies, full texts, registrations, corrections, retractions, and numerical/classification errors as revision triggers. In this work, an individual table of the preserved retained summaries was created; no external material was actually received, original verdict revised, or public deployment performed. - Why unverified: The original revision policy has been linked to the current authoring scope, but verification of future material, corrections, or public release is not an action completed in this work. - Reason for missing information: The latest external corrections/retractions, new evidence, and subsequent publication status are unverified; content QA by another author and format/UI work are the next stage. - Required materials and conditions: Complete pre-change content, material/condition/verdict events, version, original location, and current verification date - Materials to obtain first: Complete pre-change content, material/condition/verdict events, version, original location, and current verification date - Further research: When follow-up material is received, preserve existing results and historical access records, and review only the relevant rows; handle condition changes separately through freeze→apply. - Conditions for verification: Link the original revision policy with the current preservation, freezing, and application history, and assess subsequent external evidence, corrections/retractions, and publication status within the scope of material actually verified. The existence of a policy or future triggers does not substitute for verification of follow-up material or completed public release. - Why this condition is needed: Needed to prevent creation of new retained summaries or passage of technical checks from being confused with a current clinical verdict or completed public release. - Application exceptions: The historical server_deployed value in the current manuscript does not represent deployment of the new gap table. If conditions change, preserve the entire original text, then freeze the new version before applying it. - Remaining uncertainty: The latest external corrections/retractions, new evidence, and subsequent publication status are unverified; content QA by another author and format/UI work are the next stage. - Referenced methods: Material collection/selection principles in M04 §4.5–4.6; the separation of access from reading and the hyperlink contract are internally designed; M04 §4.6.3, M15 §15.3.1–15.3.3; status separation is internally designed; M04 §4.5, §4.6.3; limits on the current material conversion follow the user's scope and are internally designed - Related sources: ## Evidence and sources ### S05 The Role of Sesbania grandiflora-Derived Biotin and Bambusa arundinacea-Derived Silica Extracts in Promoting Hair, Skin, and Nail Health (Patel et al., 2025) [Source](https://ophthalmology.cureus.com/articles/385055-the-role-of-sesbania-grandiflora-derived-biotin-and-bambusa-arundinacea-derived-silica-extracts-in-promoting-hair-skin-and-nail-health-a-randomized-double-blind-placebo-controlled-clinical-study.pdf?email=) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: The arm described as a Sesbania extract in Patel 2025 is not an isolated-biotin sole-active-ingredient product. Nail PGA 0–5 measures peeling, brittleness, and surface severity, not recurrent breakage-event counts. The preserved wording records a Methods/Results endpoint-hierarchy conflict and withdrawals excluded, but this retained summary contains neither actual denominators nor a specific product amount. NCT05972512/CTRI identifies the registration as reported in the paper; the registration history/SAP are unverified. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the paper | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: full_text_pdf_endpoint_extension. Historical recorded location: Reused pp1–4/19 product and COI; newly checked p5 nail PGA methods and p11 nail Results/Figure5; Methods/Results hierarchy conflict.. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S06 NIH Office of Dietary Supplements: Biotin—Health Professional Fact Sheet [Source](https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: The NIH access record in the current 3104 material is inherited_official_extract, carrying forward the original prior verification; even then, it was not a new fetch or reverification of current status. It preserves interference signals for some thyroid assays after a single 10 mg dose (within 24 hours), and for some TSH/NT-proBNP assays in 6 healthy people exposed to 10 mg/day for 1 week. Adequate intake is not a therapeutic dose, and the absence of an established UL does not mean unlimited safety. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the official web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: inherited_official_extract. Historical recorded location: Table1; Health Risks from Excessive Biotin; Interactions with Laboratory Tests, refs9/38. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S07 FDA: Biotin Interference with Troponin Lab Tests—Assays Subject to Biotin Interference [Source](https://www.fda.gov/medical-devices/in-vitro-diagnostics/biotin-interference-troponin-lab-tests-assays-subject-biotin-interference) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: The FDA warning about falsely low results in some troponin assays is official safety context inherited by the manuscript. It does not mean an identical risk rate or stopping interval across all assays and exposures. Do not use it as evidence of efficacy for breakage frequency or as individual safety/dosing instructions. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the official web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: inherited_official_extract. Historical recorded location: Opening safety statement and paragraphs on residual assay interference. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S20 Colombo et al. 1990: Treatment of brittle fingernails and onychoschizia with biotin: scanning electron microscopy [Source](https://pubmed.ncbi.nlm.nih.gov/2273113/) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: Colombo 1990 observes thickness and surface, not direct recurrent breakage events. The healthy comparators are not a matched randomized treatment control, and event denominators are unverified. The original summary/source identifier remains an extract supplied from the earlier 866 record; the old original text was not opened in this review. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the bibliographic/abstract web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: provided_extract. Historical recorded location: historical reference record 866.json: evidence Colombo entry and corresponding citation. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | | Full text of the paper | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. The current record contains no direct URL for this material type. Bibliographic information/author uploads are not treated as publisher full text or a protocol download. Historical access level recorded for the report as a whole: provided_extract. Historical recorded location: historical reference record 866.json: evidence Colombo entry and corresponding citation. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S21 Hochman et al. 1993: Brittle nails: response to daily biotin supplementation [Source](https://pubmed.ncbi.nlm.nih.gov/8477615/) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: Hochman 1993 provides retrospective uncontrolled data on subjective hardness/splitting responses. A prespecified recurrent-event observation window, time denominator, and between-group effect have not been verified. Only the supplied earlier extract was read; a null DOI field is not described as absence of a DOI itself. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the bibliographic/abstract web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: provided_extract. Historical recorded location: historical reference record 866.json: evidence Hochman entry and citation. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | | Full text of the paper | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. The current record contains no direct URL for this material type. Bibliographic information/author uploads are not treated as publisher full text or a protocol download. Historical access level recorded for the report as a whole: provided_extract. Historical recorded location: historical reference record 866.json: evidence Hochman entry and citation. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S22 Lipner and Scher: Biotin for the treatment of nail disease: what is the evidence? [Source](https://pubmed.ncbi.nlm.nih.gov/29057689/) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: The Lipner/Scher review is a provided_review_extract from the earlier 866 record. It is preserved as discovery context and is not counted as an independent randomized replication, a current exhaustive search, or evidence of study absence. Neither the original review nor the old 866 file was opened in this review. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the bibliographic/abstract web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: provided_review_extract. Historical recorded location: historical reference record 866.json: review evidence/citation. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | | Full text of the review paper | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. The current record contains no direct URL for this material type. Bibliographic information/author uploads are not treated as publisher full text or a protocol download. Historical access level recorded for the report as a whole: provided_review_extract. Historical recorded location: historical reference record 866.json: review evidence/citation. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S23 Floersheim 1989: Treatment of brittle fingernails with biotin [Source](https://pubmed.ncbi.nlm.nih.gov/2648686/) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: The Floersheim 1989 figures are preserved: 71 people treated, 45 evaluated, and 41 with improved hardness; 2.5 mg/day for a mean of 5.5 ± 2.3 months. The type of ±, placebo comparison, event diary, and standardized observation window are unverified in the abstract. The 41 people are the number of people who responded, not recurrent-event counts per person. The English PubMed abstract was read historically; this does not represent current reading of the German original full text. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the bibliographic/abstract web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: abstract. Historical recorded location: PubMed Abstract, paragraphs on 71 treated / 45 evaluated / 41 firmer-hardness responses and treatment duration. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | | Full text of the paper | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. The current record contains no direct URL for this material type. Bibliographic information/author uploads are not treated as publisher full text or a protocol download. Historical access level recorded for the report as a whole: abstract. Historical recorded location: PubMed Abstract, paragraphs on 71 treated / 45 evaluated / 41 firmer-hardness responses and treatment duration. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S24 Chiavetta et al. 2019: Hydroxypropyl chitosan-based lacquer alone or with oral biotin [Source](https://www.researchgate.net/publication/334685659_Treatment_of_brittle_nail_with_a_hydroxypropyl_chitosan-based_lacquer_alone_or_in_combination_with_oral_biotin_A_randomized_assessor-blinded_trial) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: Chiavetta 2019 is a randomized add-on study with open treatment and blinded assessment. It compared biotin 10 mg/day added to the same lacquer in 24 people versus lacquer in 26 people over 4 months. Splitting-severity reductions of 1.4 versus 0.9 points, P=0.03; OGSS improvement of 50% or more in 80% versus 53%, P=0.05; and improvement of 1 point or more in 91% versus 73%, P=0.2, are different endpoints/response criteria. They were not converted into recurrent breakage events. Historical author HTML access and PDF download failure are distinguished from reading in this review. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the author-uploaded web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: author_posted_full_text. Historical recorded location: Author-posted accepted manuscript: pp1–2 Methods target great toenail and OGSS; pp2–3 Results; p4 funding/conflict statement. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | | Publisher full text of the paper | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. The current record contains no direct URL for this material type. Bibliographic information/author uploads are not treated as publisher full text or a protocol download. Historical access level recorded for the report as a whole: author_posted_full_text. Historical recorded location: Author-posted accepted manuscript: pp1–2 Methods target great toenail and OGSS; pp2–3 Results; p4 funding/conflict statement. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S25 Shemer et al. 2025: Biotin or Pyridoxine Versus Combined Regimen in Treatment of Onychoschizia [Source](https://jddonline.com/articles/biotin-or-pyridoxine-versus-combined-regimen-in-treatment-of-onychoschizia-S1545961625P7687X) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: The Shemer 2025 record states that retrospective comparison and complete/partial response were identified in the index. A full journal response of 403 and an empty native PubMed response prevented verification of dose, arm denominators, and standardized recurrent-event collection. These access limitations are neither negative results nor study absence; figures from commercial restatements were not adopted. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the journal web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: indexed_primary_abstract_fragments. Historical recorded location: Indexed journal/institutional abstract fragments: retrospective comparison, response categories; full journal page returned 403. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | | Full text of the paper | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. The current record contains no direct URL for this material type. Bibliographic information/author uploads are not treated as publisher full text or a protocol download. Historical access level recorded for the report as a whole: indexed_primary_abstract_fragments. Historical recorded location: Indexed journal/institutional abstract fragments: retrospective comparison, response categories; full journal page returned 403. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S26 Hexsel et al. 2017: Oral supplementation with specific bioactive collagen peptides improves nail growth and reduces symptoms of brittle nails [Source](https://www.researchgate.net/publication/318989437_Oral_supplementation_with_specific_bioactive_collagen_peptides_improves_nail_growth_and_reduces_symptoms_of_brittle_nails) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: Hexsel 2017 is an uncontrolled open-label before-and-after study of collagen peptides. Even though broken-nail frequency is reported, it is not a biotin between-group effect. Only the manuscript record of author HTML access/a direct PubMed challenge is preserved; the external original text was not read in this review. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the author-uploaded web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: author_posted_full_text. Historical recorded location: Abstract and Methods: collagen peptides, uncontrolled design, broken-nail frequency. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | | Publisher full text of the paper | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. The current record contains no direct URL for this material type. Bibliographic information/author uploads are not treated as publisher full text or a protocol download. Historical access level recorded for the report as a whole: author_posted_full_text. Historical recorded location: Abstract and Methods: collagen peptides, uncontrolled design, broken-nail frequency. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S27 Chessa et al.: Pathogenesis, Clinical Signs and Treatment Recommendations in Brittle Nails: A Review [Source](https://link.springer.com/article/10.1007/s13555-019-00338-x) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: The Chessa review provides discovery context for causes, diagnosis, treatment, and biotin references. The historical PMC challenge and publisher HTML access are distinguished. The review is not counted as a unique event-comparison trial or an eligible effect. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the review paper | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: full_text_review. Historical recorded location: Causes/diagnosis and treatment sections; biotin references. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S28 Zaraa and Richert: Nail Supplements: When, How, and Why? [Source](https://karger.com/sad/article/11/2/176/913681/Nail-Supplements-When-How-and-Why) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: Zaraa/Richert was preserved at the level of the indexed abstract and reference list for the 2024 online publication/2025 issue. This is neither full-text primary-outcome verification nor an independent clinical trial. The PMC challenge reflects the historical scope of access; no query was made in this review. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the publisher web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: indexed_review_metadata_abstract. Historical recorded location: Publisher indexed abstract and reference list; PMC challenge. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | | Full text of the review paper | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. The current record contains no direct URL for this material type. Bibliographic information/author uploads are not treated as publisher full text or a protocol download. Historical access level recorded for the report as a whole: indexed_review_metadata_abstract. Historical recorded location: Publisher indexed abstract and reference list; PMC challenge. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S29 ClinicalTrials.gov NCT05800496: nail supplement trial record [Source](https://clinicaltrials.gov/study/NCT05800496) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: NCT05800496 is limited to the shell/indexed nail PGA wording and the historical API failure. Full composition, protocol, status, results, and event definition are unverified. It is not counted as a negative trial, a terminated trial, or a trial with 0 participants. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the registry web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: registration_shell_and_indexed_snippet. Historical recorded location: Page shell; indexed nail PGA wording; API failed. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | | Full text of the study protocol/analysis plan | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. The current record contains no direct URL for this material type. Bibliographic information/author uploads are not treated as publisher full text or a protocol download. Historical access level recorded for the report as a whole: registration_shell_and_indexed_snippet. Historical recorded location: Page shell; indexed nail PGA wording; API failed. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S30 ClinicalTrials.gov NCT07373574: Effects of Dietary Supplements on Nail and Hair Health [Source](https://clinicaltrials.gov/study/NCT07373574) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: NCT07373574 records search discovery of a nail/hair title and a page shell/API failure. Current status, timing, composition, and results have not been verified. Do not infer dates or recruitment status from the number. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the registry web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: registration_shell_and_indexed_metadata. Historical recorded location: Page shell; API failed. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | | Full text of the study protocol/analysis plan | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. The current record contains no direct URL for this material type. Bibliographic information/author uploads are not treated as publisher full text or a protocol download. Historical access level recorded for the report as a whole: registration_shell_and_indexed_metadata. Historical recorded location: Page shell; API failed. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ### S31 ClinicalTrials.gov NCT05972512: identifier reported by Patel study [Source](https://clinicaltrials.gov/study/NCT05972512) Materials actually read: The relevant Korean and English summaries and bibliographic records in the retained manuscript were read. The linked external original material was not read in this review. Findings recorded in the summary: NCT05972512 is the same family identifier reported by the Patel paper S05. The actual registry endpoint hierarchy, changes, and SAP were not historically retrievable; only a shell remains. The paper and registration are not counted as two independent trials. Record level: This content is recorded in the retained manuscript. It is not the result of a new comparison against external original material in this review. Independent replication: Only the family_id and citation relationships in the current source are linked. The 15 citations and 9 structured families are not a count of independent eligible direct trials. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Full text of the registry web document | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. This is the entry URL recorded for the retained material; it does not verify current access or full-text acquisition. Historical access level recorded for the report as a whole: registration_shell. Historical recorded location: Article S05 registration citation; actual registry page shell only. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | | Full text of the study protocol/analysis plan | Unverified (no external query in this review) | Access not attempted | Not read | Material type, bibliographic links, and historical reading are separate from the fact that this external material was not read in this review. No access to this external material was attempted and its full text was not read in this review. What was read in this review consists of the retained report summaries. The current record contains no direct URL for this material type. Bibliographic information/author uploads are not treated as publisher full text or a protocol download. Historical access level recorded for the report as a whole: registration_shell. Historical recorded location: Article S05 registration citation; actual registry page shell only. This historical report-level status is not inherited as the current reading status of each material. The actual historical access date for each material is unverified. The retained manuscript review date of 2026-09-15 is not the access date for the original material. | ## Review criteria and methods These are Chamgap's own application conditions, informed by the relevant sections of official methodological guidance. They do not constitute official assessment-tool certification or a new efficacy score. - M03 [Cochrane Handbook 6.5 (2024), chapter updated 2023-08](https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-03) · §3.1, §3.2.1–3.2.3, MECIR C5/C7/C13 · Clearly document the question, eligibility conditions, and reasons for changes, and distinguish variations in interventions. · Reuse of original bytes, SHA, and historical methodological principles preserved in 1585. This does not represent new reading of the full methodological texts, application of official methods, or certification in this review. - M04 [Cochrane Handbook 6.5.1 (2025), chapter updated 2025-03](https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-04) · §4.5, §4.6.1–4.6.3, MECIR C42 · Distinguish and link studies and reports, and do not omit studies solely because outcomes were unreported. · Reuse of original bytes, SHA, and historical methodological principles preserved in 1585. This does not represent new reading of the full methodological texts, application of official methods, or certification in this review. - M08 [Cochrane Handbook 6.5 (2024), chapter updated 2019-10](https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-08) · §8.1–8.2.3, Table 8.2.a · Fix the outcome and effect of interest when reviewing randomization, deviations, missing data, measurement, and selective reporting. · Reuse of original bytes, SHA, and historical methodological principles preserved in 1585. This does not represent new reading of the full methodological texts, application of official methods, or certification in this review. - M15 [Cochrane Handbook 6.5 (2024), chapter updated 2023-08](https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-15) · §15.2.4, §15.3.1–15.3.3 · Distinguish effect estimates, intervals, importance, and applicability. Sample size alone does not determine precision. · Reuse of original bytes, SHA, and historical methodological principles preserved in 1585. This does not represent new reading of the full methodological texts, application of official methods, or certification in this review. - M19 [Cochrane Handbook 6.5 (2024), chapter updated 2019-10](https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-19) · §19.1.2, §19.2.1–19.2.4 · Harm questions may require different designs, populations, and follow-up from efficacy questions. Case reports do not establish incidence. · Reuse of original bytes, SHA, and historical methodological principles preserved in 1585. This does not represent new reading of the full methodological texts, application of official methods, or certification in this review. ## What the statuses mean - Met: The question identity/record conditions were verified within the currently preserved scope. This does not establish clinical efficacy. - Partly verified: Some information is available, while gaps in direct conditions/material remain. - Unverified: The actual material and values needed for the selected condition could not be verified within the current scope. - Not met: The verified ingredient, endpoint, or comparison does not meet the selected direct conditions. This is not a verdict of no effect. - Conflicting information: A wording inconsistency preserved within the same report. This is distinguished from differences between analyses or current independent verification of the original full text. - Not read: The external material was not actually read in this review. ## Change history 2026-11-03 · Public page/materials 1.0. The public interface and data were prepared from the existing 42 items. No new clinical search, change in verification status, or scoring was performed.