Biotin (Vitamin B7) for Hair Loss
For people without a genuine biotin deficiency, biotin supplements have no proven effect on hair loss, and high doses can dangerously skew lab tests. Eat a balanced diet and pursue evidence-based treatments instead.
Why this grade7-layer evidence engine
Two high-quality systematic reviews drive the Counter-Evidence grade. Lipner 2018 (PMID 29438761) found that all 18 reported cases of benefit involved an underlying cause of deficiency, such as inherited biotinidase deficiency, with no randomized trial showing benefit in non-deficient people. Patel 2017 (PMID 28879195) likewise found insufficient data and advised against routine supplementation absent clinical signs of deficiency.
Observational data reinforce this: Trüeb 2016 (PMID 27601860) noted low serum biotin in some women with hair loss but established no causal link or treatment efficacy. The NIH Office of Dietary Supplements states hair claims rest, at best, on a few case reports, only in children, and the UK NHS notes a varied diet plus gut bacteria already supply enough biotin.
Safety also weighs against routine use. The FDA warns high-dose biotin causes incorrect lab results and has linked it to a death from falsely low troponin. EFSA's 'maintenance of normal hair' wording is a biochemical cofactor claim, not evidence that biotin treats or regrows lost hair.
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 = 0.34
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 無高階證據可裁決
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status