Vitamin B1 (Thiamine) for Neuropathy
Thiamine (vitamin B1) reliably reverses nerve damage caused by an actual thiamine deficiency, such as alcoholic neuropathy or beriberi, but the evidence that it helps non-deficient diabetic neuropathy is weak, short-term, and largely funded by manufacturers. For people who are not deficient, B1 and its derivative benfotiamine are not an established treatment.
Why this grade7-layer evidence engine
The grade hinges on two very different situations that share one name. When neuropathy is caused by a genuine thiamine shortfall (chronic alcohol use, malnutrition, beriberi), repletion clearly helps: a small alcoholic-neuropathy trial (PMID 9872352) improved symptoms and sensory function, and the FDA, WHO, Mayo Clinic and Cleveland Clinic all recognize thiamine as the standard fix for deficiency. That part is mechanistically sound and uncontested.
For the far more common non-deficient diabetic neuropathy, the proof is thin. The supporting trials are short (3-6 weeks) and small: BEDIP (PMID 16320869, n=40) and a B-vitamin combination study (PMID 8886748, n=24) were positive but underpowered, while the largest trial, BENDIP (PMID 18473286, n=165), reached significance only in the 600 mg/day per-protocol subgroup (p=0.033) and missed in the full intention-to-treat analysis. A systematic review (PMID 20188835) judged this body of evidence weak and inconclusive outside deficiency states.
Two further problems hold the rating at weak. Nearly all the diabetic-neuropathy trials were funded by the benfotiamine manufacturer and relied on subjective symptom scores, raising bias concerns, and there are no long-term or hard endpoints. Regulators (EFSA, NHS) authorize only general nervous-system function claims, not disease treatment, and neurology and diabetes guidelines (AAN, ADA) do not list B1 or benfotiamine as a recommended therapy.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.502
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status