Legacy AI grade · Sources dated 2026-06-01. Not expert reviewed. Coverage is limited to the listed sources. About the new summary workflow
Procyanidin B-2 (Apple Polyphenol) for Alopecia Areata
There is no human evidence that procyanidin B-2 (apple polyphenol) treats alopecia areata. Every existing human trial was conducted in a different, unrelated condition, so its benefit for autoimmune patchy hair loss is unverified, not established.
Why this grade7-layer evidence engine
A PubMed search found zero clinical trials of procyanidin B-2 in alopecia areata of any design. The only human RCTs (Takahashi et al., PMID 11194183 and PMID 11406858, each n=29) enrolled men with androgenetic alopecia (pattern baldness), a fundamentally different disease, and a 2018 systematic review of complementary alopecia treatments (PMID 30815439) lists the compound only under androgenetic alopecia, omitting it from the alopecia areata section.
Mechanism also argues against extrapolation. A laboratory study (PMID 11841365) shows procyanidin B-2 acts by downregulating protein kinase C isozymes and pushing follicles from rest into the growth phase. That hair-cycle pathway is off-target for alopecia areata, which is driven by a CD8+ T-cell autoimmune attack on the follicle and is treated with corticosteroids and JAK inhibitors.
Authorities add nothing supportive: the FDA recognizes apple polyphenol extract only as a safe food ingredient (GRAS), EFSA rejected procyanidin health claims because a cause-and-effect relationship has not been established, and major clinical bodies do not address it. With no condition-specific data and industry-funded source studies, the engine rates it Unverified (U) pending more evidence.
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 = 0.406
- 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 — | C→U 因 scope.conflation_risk=true 且 L11 獨評較低 (B7-2 tier cap)
- detect_disputes — 偵測到 0 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status