Procyanidin B-2 (Apple Polyphenol) for Androgenetic Alopecia
Topical procyanidin B-2 (apple polyphenol) has only weak, disputed evidence for male androgenetic alopecia: a few small, positive early trials exist, but all come from one industry-funded team and have never been independently replicated. It is not an established hair-loss treatment.
Why this grade7-layer evidence engine
The grade rests on three small double-blind RCTs of a 1% topical tonic in Japanese men with AGA. They were directionally positive: the 2005 trial (PMID 17168871, n=43) reported 78.6% of treated men with increased hair count versus 9.1% on vehicle (p<0.001), and the 2001 trial (PMID 11406858, n=29) showed roughly +6 hairs/0.25 cm2 over placebo (p<0.001). An animal/mechanism study (PMID 11841365) proposed PKC-isozyme modulation, while the 2000 trial (PMID 11194183, n=29) gave similar results.
These signals are heavily discounted. Every human and mechanistic study comes from a single Takahashi-led group funded by Kyowa Hakko/Asahi, the apple-polyphenol supplier, with cumulative enrollment near 100 men, single-center, and zero independent replication in over 20 years. EFSA found that for proanthocyanidins 'a cause and effect relationship has not been established' (for circulatory/antioxidant claims), and the FDA recognizes apple polyphenol extract only as GRAS for food, not as a hair treatment.
No major clinical body (NIH ODS, Mayo, Cleveland Clinic, Harvard Health) or dermatology guideline (AAD, ISHRS, EADV) lists it for AGA, and the trials used a 1% topical tonic, so oral apple-polyphenol capsules cannot be assumed equivalent. Given a plausible mechanism but a thin, conflicted, unreplicated base, a weak and disputed grade is appropriate; finasteride and minoxidil remain the evidence-backed options.
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 = 0.464
- 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 1 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status