Verdict No. 3021 · Search date 2026-09-07 · Methodology v1.0
Oral vitamin C,
does it really help with Prevention of CRPS-I after distal-radius fracture or surgery?
30-Second Summary
C
Evidence Grade C · 54 · Safety caution
The English and Portuguese 2025 versions have different identifiers but represent one cohort.
High oral doses can cause gastrointestinal effects. Trial-specific adverse-event counts remain limited.
What the
research showsGrade C with 54 points. Early trials and a 2025 surgical trial reported fewer cases, but a 336-person double-blind trial found no benefit. Surgery, diagnostic criteria, and dose differ.
research showsGrade C with 54 points. Early trials and a 2025 surgical trial reported fewer cases, but a 336-person double-blind trial found no benefit. Surgery, diagnostic criteria, and dose differ.
What the
ads claimGuarantees of prevention or assumptions that higher doses work better erase the differences between schedules and sparse-event estimates.
ads claimGuarantees of prevention or assumptions that higher doses work better erase the differences between schedules and sparse-event estimates.
Useful facts when choosing a product
- This verdict concerns single-ingredient oral vitamin C and does not automatically include foods, combinations, or intravenous infusion.
- Trials with different doses, durations, and populations were not treated as interchangeable.
- High oral doses can cause gastrointestinal effects; caution is warranted with stone risk, kidney disease, or iron overload.
Chamgap Semantic Classification Code
Permanent code issued
S.vitamin-c.oral.crps-type-1-incidence.prevent.placeboSupplements and nutraceuticals > Vitamin C > Oral > CRPS-I incidence > Prevention claim > Placebo
Permanent semantic code issued; surgical status and diagnostic-criteria differences remain in exact fields. 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 C |
| Source or part used | Purified nutrient. Feedstock, manufacturing process and country are unverified; plant part is not applicable. |
| Formulation or processing | Single-ingredient ascorbic acid supplement; unverified tablet/capsule, salt and excipient details are flagged by study. |
| Route | Oral |
| Dose | Early doses200/500/1500 mg/day for50 days; later500 mg for90 days or1 g for60 days |
| Duration | One year,90 days and24 weeks separated |
| Population | Conservatively treated wrist fractures, older fracture patients and adult surgical patients separated |
| Effect or condition | CRPS-I prevention after distal-radius fracture or surgery |
| Primary endpoint | Diagnosed CRPS-I; older RSD criteria separated from Budapest criteria |
| Comparator | Matched placebo or standard care; surgical and nonsurgical cohorts separated |
| Duplicate-detection key | vitamin-c|oral|distal-radius-fracture-surgery|crps-1-prevention|diagnosed-crps-1 |
Gap Measurement · Verdict 3021 · C 54
What the research actually shows
Trials supplemented patients briefly after fracture and assessed CRPS over subsequent months; they did not test every fracture or operation.
Why this is classified as C (54)
A clinical-event endpoint and independence are strengths, but key trials conflict and the new positive study is small. EX and B2 limits yield C with 54 points.
Counterpoint. The 2022 CRPS guideline described usefulness as unproven; it is not a guideline incorporating the later 2025 trial.
Rejudgment record. Independent Codex cross-check — One page, one route, one population, one claim, one principal comparator
Scoring profile behind this grade
| Endpoint | H | Hard endpoint - actual events such as death |
| Replication | R0 | Trials conflict in direction |
| Independence | I2 | Decisive evidence is publicly or non-profit funded |
| Effect size | EX | The clinical size of the effect could not be judged |
| Precision | CX | No pooled confidence interval could be confirmed |
The scoring table and the verdict agree (C).
Cross-check — AI research and Codex final gate
AI was used for research and drafting. Blind grading, adversarial audit, and the methodology boundary rules were then reapplied before Codex performed the final evidence, grade, copy, and build checks. If a grade cannot be narrowed, both evidence positions and their reasons are published.
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Effect of vitamin C on frequency of reflex sympathetic dystrophy in wrist fractures: a randomised trial. | Double-blind conservative-fracture RCT | 65 | Unverified | Older RSD/CRPS definition | 4/54vs14/65wrists;reported risk difference15percentage points(95%CI2–26) | Initial positive;8 exclusions;people≠wrists |
| Can vitamin C prevent complex regional pain syndrome in patients with wrist fractures? A randomized, controlled, multicenter dose-response study | Double-blind multicentre dose-response RCT | 99 | Unverified | CRPS | 8/328vs10/99 overall,P=.002;RR200mg.41(.13–1.27),500mg.17(.04–.77),1500mg.17(.04–.75),all95%CI | Same main investigators asC1;not independentR2 |
| The influence of vitamin C on the outcome of distal radial fractures: a double-blind, randomized controlled trial | Independent double-blind RCT | 336 | Unverified | DASH primary;CRPS secondary | No1-year CRPS benefit;6-week nondisplaced subgroup P=.022 is not global primary harm | Important opposing result with endpoint limits |
| Vitamin C in Complex Regional Pain Syndrome in Patients with Distal Radius Fracture | Masked placebo surgical trial | 64 | No external funding/COI declared | Budapest CRPS;prespecified hierarchy unverified | 12weeks0/58vs7/64,P=.014;24weeks0/58vs8/64,P=.007;net95%CI unverified | Positive completer data;language versions are one cohort;table denominator typo flagged |
Receipt — 5 References
Of 5 cited sources, 4 had limited original-page access (blocked or summary-only) and were verified via index/summary, marked partial; the rest were verified at the original page. As of 2026-09-07.
Zollinger PE et al.. Effect of vitamin C on frequency of reflex sympathetic dystrophy in wrist fractures: a randomised trial.. Lancet. 354:2025–2028. 1999. PMID: 10636366; DOI: 10.1016/S0140-6736(99)03059-7.
partialZollinger PE et al.. Can vitamin C prevent complex regional pain syndrome in patients with wrist fractures? A randomized, controlled, multicenter dose-response study. J Bone Joint Surg Am. 89(7):1424–1431. 2007. PMID: 17606778; DOI: 10.2106/JBJS.F.01147.
partialEkrol I et al.. The influence of vitamin C on the outcome of distal radial fractures: a double-blind, randomized controlled trial. J Bone Joint Surg Am. 96(17):1451–1459. 2014. PMID: 25187584; DOI: 10.2106/JBJS.M.00268.
partialde Azevedo Filho FAS, Blunck RM, Ali AY, Fucs PMMB, Cotias RB. Vitamin C in Complex Regional Pain Syndrome in Patients with Distal Radius Fracture. Rev Bras Ortop (Sao Paulo). 60(3):s00451810402; online2025-08-25 / eCollection2025-06. 2025. PMID: 40860294; PMCID: PMC12377947; DOI: 10.1055/s-0045-1810402.
partialEvaniew N et al. Vitamin C to prevent complex regional pain syndrome in patients with distal radius fractures: a meta-analysis of randomized controlled trials. 2015. PMID: 26197022.
checkedResearch and draft: AI used · Cross-check: blind grading and adversarial audit
Final verification and publication gate: Codex · Verification cutoff: 2026-09-07 · Corrections: none
Final verification and publication gate: Codex · Verification cutoff: 2026-09-07 · Corrections: none
Cite this verdict
[Chamgap] Oral Vitamin C After Distal-Radius Fracture or Surgery—CRPS-I Results Remain Conflicting — Evidence Grade C·54. 5 cited sources checked. Source: https://chamgap.com/en/verdicts/joint-bone/oral-vitamin-c-distal-radius-crps-prevention/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
What 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.