Oral vitamin B6 supplements and medicines: clinical sensory neuropathy risk
conclusionOral vitamin B6 from supplements or medicines can cause clinical sensory neuropathy. Causality is particularly supported for high-dose pyridoxine. This does not establish the same risk rate for every vitamer, dose, or user.
boundaryThe evidence does not support claiming that every low dose is safe or that all vitamin B6 forms, products and doses share one risk rate. Nutritional upper limits and labeling or sale rules are not clinical toxicity thresholds.
Four separate assessment dimensions
| Effect direction and size | Oral vitamin B6 from supplements or medicines can cause clinical sensory neuropathy. Causality is particularly supported for high-dose pyridoxine. This does not establish the same risk rate for every vitamer, dose, or user. |
|---|---|
| Evidence certainty | Causality is supported for high-dose pyridoxine, while population risk, minimum risk dose and duration remain unverified. |
| Applicability | New or worsened clinical sensory neuropathy in adults exposed orally to supplements or medicines. Causality is clearest for high-dose pyridoxine; form-specific and dose-specific risks are not pooled. |
| Safety | Oral vitamin B6 from supplements or medicines can cause clinical sensory neuropathy. Causality is particularly supported for high-dose pyridoxine. This does not establish the same risk rate for every vitamer, dose, or user. This is not an individual treatment or dosing instruction. New or worsening tingling, burning, numbness, or balance difficulty warrants clinical assessment of all products and alternative causes. Do not self-escalate nonessential supplements or independently stop or replace prescribed treatment. |
Because this is a safety question, the A-F efficacy grade and numeric efficacy score do not apply. Document quality B is not a hazard grade or probability.
Useful facts when choosing a product
- Pyridoxine, pyridoxine hydrochloride, pyridoxal, pyridoxal-5-phosphate (PLP/P5P), and pyridoxamine are related vitamers or salts, not automatically identical formulations or equally neurotoxic clinical exposures. A report of pyridoxine alone is not relabeled as the hydrochloride salt. Clinical assurance that PLP is free of neuropathy risk was not established.
- The 1.4–100 mg range in the 2018 Lareb abstract is content per tablet. Without verified frequency, multiple-product use, and actual content, it was not converted into total daily intake or a risk threshold.
- The US FNB adult nutritional upper limit is 100 mg/day; the EFSA adult limit is 12 mg/day, also applying to adult pregnancy and lactation. Jurisdictions and risk-assessment methods differ. These are not treatment recommendations, clinical toxicity thresholds, or guarantees of no risk below them.
- Australia TGA requires a warning for supplementary medicines providing more than 10 mg of B6 daily; the labeling transition deadline was 2023-03-01. This is a labeling rule applicable at the 2026-09-15 cutoff, not a biological threshold at which risk begins.
- The Australian pharmacist-only change for products above 50 mg/day through 200 mg/day is scheduled for 2027-06-01 and remains future at 2026-09-15. It is distinguished from prescription control above 200 mg/day. Labeling thresholds, sale categories, and nutritional upper limits are different rules.
- This is not an individual treatment or dosing instruction. New or worsening tingling, burning, numbness, or balance difficulty warrants clinical assessment of all products and alternative causes. Do not self-escalate nonessential supplements or independently stop or replace prescribed treatment.
Chamgap Semantic Classification Code
Permanent code issued
S.vitamin-b6-supplemental-medicinal.oral.clinical-sensory-neuropathy-risk.increase.unexposed-or-lower-exposureSubstances and nutrients > Oral supplemental or medicinal vitamin B6 exposure > Oral > Clinical sensory neuropathy risk > Increased risk > Unexposed or lower exposure
Safety-only assessment. The semantic code identifies exposure and harm claim; it contains neither an efficacy grade/score nor a hazard probability. S is the primary exposure class while the medicinal M stratum remains separately preserved in the record. The code identifies the intervention and claim; it never contains the evidence grade, score, or safety result.
Exact Claim Classification
These independent facets prevent evidence from different forms, routes, populations, effects, and comparators from being mixed.
| Intervention class | S · Supplement or nutraceutical |
|---|---|
| Canonical ingredient or intervention | Vitamin B6 exposure: pyridoxine, pyridoxine hydrochloride, pyridoxal, PLP/P5P, and pyridoxamine are distinguished; causality is clearest for high-dose pyridoxine |
| Source or part used | Oral B6 from supplements or medicines. Ordinary and fortified food are separate exposure strata; manufacturing origin such as synthesis or fermentation is unverified by study |
| Formulation or processing | Single tablets/capsules and combination products distinguished. Exact salt, brand, release, purity and batch are unverified for many cases; formulations are not equated |
| Route | Oral exposure. Parenteral or animal dosing is not transferred to human oral incidence |
| Dose | Preserved by study, not combined into one risk dose. Low-dose reports separated from high-dose experiments; actual total and measured-versus-labeled amounts remain unverified when absent |
| Duration | Exposure, onset and post-withdrawal follow-up kept separate. Minimum risk duration at low doses and several individual exposure periods unverified |
| Population | Primarily orally exposed adults; healthy volunteers, pre-existing neuropathy, TB/HIV, and elderly cases separated. Individual risks in children, pregnancy or renal disease unverified |
| Effect or condition | Can supplemental or medicinal B6 exposure cause new or worsened clinical sensory neuropathy? |
| Primary endpoint | New or worsened clinical sensory neuropathy. Studies unable to separate these events are marked as mixed; PLP/QST/nerve-conduction change alone excluded |
| Comparator | Unexposed or lower exposure preferred. Uncontrolled experiments and spontaneous reports have no comparator; CIAP case-control and TB dose comparisons are contextual |
| Duplicate-detection key | vitamin-b6-supplemental-medicinal|oral|dose-by-study|orally-exposed-adults|new-or-worsened-clinical-sensory-neuropathy|duration-by-study|unexposed-or-lower-exposure |
What the research actually shows
Oral vitamin B6 from supplements or medicines can cause clinical sensory neuropathy. Causality is particularly supported for high-dose pyridoxine. This does not establish the same risk rate for every vitamer, dose, or user.
Berger exposed 5 volunteers to pyridoxine at 1 or 3 g/day. Symptoms occurred earlier at the higher dose, and worsening could continue for 2–3 weeks after withdrawal. This small experiment without an unexposed control does not supply a population incidence rate.
The generalized Berger abstract and EFSA participant-level extraction do not agree on the number with clinical symptoms. The EFSA table includes a participant with sensory-test change but no clinical symptoms. Clinical disease in all 5 participants or a 100% attack rate is therefore not asserted.
The 2025 Lareb analysis covers 224 reports from 2007-08 through 2023-12-31. The earlier 2018 analysis of 90 reports and the intermediate count cited by EFSA overlap the same reporting lineage. They are not added together; no incidence rate is calculated without an exposed denominator, consistent clinical confirmation, and duration data.
Among 32 reports selected by TGA through 2022-08-05, 21 involved reported exposure of 50 mg/day or less and 9 involved multiple products. These categories may overlap. This describes selected reports, not the probability of disease among users at that dose or proof of causality for every low dose.
In a terizidone-treated multidrug-resistant tuberculosis cohort, pyridoxine at 200 versus 150 mg/day was associated with an adjusted HR of 2.79, P=0.01, for new or worsened peripheral neuropathy. Exposure was not randomized. HIV, tuberculosis, co-medication, and prescribing indications preclude treating this as a causal RR for general supplement users.
A series of 3 elderly patients reported pyridoxine at 600 mg/day in B1-B6-B12 combination tablets for 3–10 years, with no significant neuropathy or gait improvement after 2 years of withdrawal. It does not estimate the incidence with single-ingredient B6 or the probability of permanent damage.
In a case-control study of 381 CIAP patients and 140 controls, median blood B6 values of 99 versus 109 nmol/L did not differ significantly (P=0.58). Supplement use was reported as 31% versus 22%, OR 1.7 (95% CI 1.0–2.7; P=0.032). This is an association between prevalent disease and supplement use, not an incidence estimate for new B6 toxicity or a guarantee of safety.
An established minimum risk dose or duration, or an individual no-risk boundary, was not identified. The dose–onset relationship at high doses and low-dose spontaneous-report signals have different evidential strength. Cumulative intake was not calculated without verified individual daily exposure, duration, and adherence.
The US FNB adult nutritional upper limit is 100 mg/day; the EFSA adult limit is 12 mg/day, also applying to adult pregnancy and lactation. Jurisdictions and risk-assessment methods differ. These are not treatment recommendations, clinical toxicity thresholds, or guarantees of no risk below them.
Australia TGA requires a warning for supplementary medicines providing more than 10 mg of B6 daily; the labeling transition deadline was 2023-03-01. This is a labeling rule applicable at the 2026-09-15 cutoff, not a biological threshold at which risk begins.
The Australian pharmacist-only change for products above 50 mg/day through 200 mg/day is scheduled for 2027-06-01 and remains future at 2026-09-15. It is distinguished from prescription control above 200 mg/day. Labeling thresholds, sale categories, and nutritional upper limits are different rules.
This is not an individual treatment or dosing instruction. New or worsening tingling, burning, numbness, or balance difficulty warrants clinical assessment of all products and alternative causes. Do not self-escalate nonessential supplements or independently stop or replace prescribed treatment.
Why the safety label is Warning
Oral vitamin B6 from supplements or medicines can cause clinical sensory neuropathy. Causality is particularly supported for high-dose pyridoxine. This does not establish the same risk rate for every vitamer, dose, or user.
Berger exposed 5 volunteers to pyridoxine at 1 or 3 g/day. Symptoms occurred earlier at the higher dose, and worsening could continue for 2–3 weeks after withdrawal. This small experiment without an unexposed control does not supply a population incidence rate.
In a terizidone-treated multidrug-resistant tuberculosis cohort, pyridoxine at 200 versus 150 mg/day was associated with an adjusted HR of 2.79, P=0.01, for new or worsened peripheral neuropathy. Exposure was not randomized. HIV, tuberculosis, co-medication, and prescribing indications preclude treating this as a causal RR for general supplement users.
The 2025 Lareb analysis covers 224 reports from 2007-08 through 2023-12-31. The earlier 2018 analysis of 90 reports and the intermediate count cited by EFSA overlap the same reporting lineage. They are not added together; no incidence rate is calculated without an exposed denominator, consistent clinical confirmation, and duration data.
An established minimum risk dose or duration, or an individual no-risk boundary, was not identified. The dose–onset relationship at high doses and low-dose spontaneous-report signals have different evidential strength. Cumulative intake was not calculated without verified individual daily exposure, duration, and adherence.
Counterevidence and limits. In a case-control study of 381 CIAP patients and 140 controls, median blood B6 values of 99 versus 109 nmol/L did not differ significantly (P=0.58). Supplement use was reported as 31% versus 22%, OR 1.7 (95% CI 1.0–2.7; P=0.032). This is an association between prevalent disease and supplement use, not an incidence estimate for new B6 toxicity or a guarantee of safety. The CIAP authors considered a causal relationship unlikely in light of daily dose, cumulative dose, duration, and blood-level findings. Reverse causation from supplement use for existing symptoms and the selected disease phenotype matter. This contrary or qualifying evidence is retained; not all neuropathy is attributed to B6. The generalized Berger abstract and EFSA participant-level extraction do not agree on the number with clinical symptoms. The EFSA table includes a participant with sensory-test change but no clinical symptoms. Clinical disease in all 5 participants or a 100% attack rate is therefore not asserted.
Review performed and remaining limitations
Pyridoxine, pyridoxine hydrochloride, pyridoxal, pyridoxal-5-phosphate (PLP/P5P), and pyridoxamine are related vitamers or salts, not automatically identical formulations or equally neurotoxic clinical exposures. A report of pyridoxine alone is not relabeled as the hydrochloride salt. Clinical assurance that PLP is free of neuropathy risk was not established. The 1.4–100 mg range in the 2018 Lareb abstract is content per tablet. Without verified frequency, multiple-product use, and actual content, it was not converted into total daily intake or a risk threshold. The cohort recruited 144 participants and reported neuropathy in 50 (35% as reported). Exposure-group denominators and events, the adjusted HR confidence interval, exact follow-up, and separate new-onset and worsening counts were not verified from the abstract. The composite neuropsychiatric event rate was not used as a sensory-neuropathy incidence rate. The CIAP authors considered a causal relationship unlikely in light of daily dose, cumulative dose, duration, and blood-level findings. Reverse causation from supplement use for existing symptoms and the selected disease phenotype matter. This contrary or qualifying evidence is retained; not all neuropathy is attributed to B6. Official assessment describes improvement after withdrawal in some cases, but recovery speed and completeness cannot be guaranteed for an individual. Worsening may continue briefly after withdrawal or impairment may persist. Individual verified rechallenge data were insufficient in this extraction and were not treated as a separate confirmation of causality. Alternative causes include diabetes, B12 deficiency, alcohol, kidney disease, and chemotherapy or tuberculosis medicines. An elevated PLP level alone does not establish cause; baseline symptoms, exposure timing, examination, other investigations, and withdrawal course must be considered. Total intake across products is added only when labeled amounts and use are verified. Form-specific toxicity rates or individually safe doses were not verified for kidney or liver impairment, pregnancy or lactation, children, or pre-existing neuropathy. Reports of low B6 indices in kidney disease are not evidence that high-dose supplementation is safe. Metabolic disease, deficiency, or specific medicines requiring B6 treatment need a separate benefit–risk assessment. Exact product salt, purity, batch, measured versus labeled amount, actual frequency, total duration, baseline kidney or liver function, and co-medication remain unverified in several sources. Numerical findings from inaccessible originals were not filled in. Registration, correction, and retraction checks are limited to the recorded search scope and do not guarantee all literature is free of issues. Original candidates describing recovery and absence of neuropathy after long exposure were also located, but sources without accessible full text or a complete abstract were not used quantitatively. Inaccessibility was not treated as a null result, and favorable or unfavorable titles alone did not determine causality.
Search scope and limitations. Executed searches, access and selection records are retained in the transfer package.
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Berger et al. 1992 | Uncontrolled prospective high-dose exposure; 1 or 3 g/day | 5 volunteers; clinical numerator conflicts across sources | {"value": null, "status": "not_verified", "reason": "Not verified from the accessed source"} | Clinical sensory symptoms/signs; QST, conduction and PLP separated | Earlier symptoms at the higher dose; worsening may continue 2–3 weeks after withdrawal. No 5/5 rate claimed | Supports high-dose pyridoxine causality, not population incidence |
| Overlapping Lareb report series 2018/2025 | Spontaneous-report series; earlier 90 overlap later 224 | 224 reports in 2025 analysis; no exposed denominator | {"2018": "No funding received for preparation as declared", "2025": {"value": null, "status": "not_verified", "reason": "Full funding statement not verified; absence not inferred"}} | Reported neuropathy; incomplete clinical confirmation and incident/worsened separation | Safety signal, but actual daily exposure, duration and incidence are unverified | Used as a safety signal; overlapping counts not summed |
| Australian TGA selected reports | Regulatory spontaneous-report safety review | 32 reports; 21 at <=50 mg/day and 9 with multiple products (categories may overlap) | {"status": "official_regulatory_activity"} | Reported peripheral neuropathy; elevated blood B6 alone separated from clinical events | Minimum risk dose/duration and exposed-user incidence cannot be estimated | Supports a possible lower-dose signal and labeling warning, not a biological threshold |
| Visser et al. 2014 | Case-control study of prevalent CIAP versus healthy controls | 381 cases and 140 controls | {"status": "not_verified", "note": "EFSA cites foundation support but original full funding and role were not independently confirmed"} | Association with prevalent CIAP; not incident toxic neuropathy | Supplement use OR 1.7 (95% CI 1.0–2.7); blood B6 difference P=0.58 | Retained as qualifying evidence; neither a safety guarantee nor causal incidence |
| Kulkantrakorn 2014 case series | Three elderly cases; B1/B6/B12 combination | 3 patients aged 80, 83 and 83 | {"value": null, "status": "not_verified", "reason": "Not verified from the accessed source"} | Sensory ataxic neuropathy and gait impairment | Pyridoxine 600 mg/day for 3–10 years; no significant improvement after 2 years off exposure | Warns of persistent harm; cannot estimate permanent-harm probability |
| Court et al. 2021 TB cohort | Prospective terizidone-treated MDR-TB cohort; nonrandom B6 dose | 144 recruited; 50 neuropathy events (incident/worsened combined) | {"status": "indexed", "finding": "PubMed lists NIH/NIAID and Wellcome grants; full sponsor roles and product supply not verified"} | Incident or worsened peripheral neuropathy | 200 vs 150 mg/day adjusted HR 2.79, P=0.01; CI and arm events unverified | Contextual dose comparison; not a causal RR for general supplement users |
Receipt — 15 References
Evidence access cutoff: 2026-09-15. Each citation states its actual access level (full-text transcription, abstract, index, or other) and remaining limitations. Bibliographic checking does not certify the study results or treatment efficacy.
Technical integration by: Codex · Evidence date: 2026-09-15 · Corrections: none
Cite this safety assessment
[Chamgap] Oral vitamin B6 supplements and medicines: clinical sensory neuropathy risk — Efficacy grade N/A · Safety warning. 15 cited sources checked. Source: https://chamgap.com/en/verdicts/cognition/oral-vitamin-b6-clinical-sensory-neuropathy-risk/ · CC BY 4.0What this document does and does not do
Chamgap is an information source. It reports what research has and has not confirmed; it does not tell readers what to take or buy. That decision belongs to readers and, when needed, medical or legal professionals. This verdict reflects literature available up to the search date and may change as new research appears. Nothing here is medical advice.