Finasteride for Androgenetic Alopecia
For men with androgenetic alopecia, daily oral finasteride is consistently shown to slow shedding and modestly regrow hair, but the benefit reverses within about a year of stopping and carries sexual side-effect warnings. The evidence does not extend to women, where results are negative or too limited to support use.
Why this grade7-layer evidence engine
Multiple large double-blind RCTs in men point the same direction: the Propecia phase III pivotal trial (PMID 9777765, n=1879), a frontal hair-loss trial (PMID 10365924, n=326), and a trial in men aged 41-60 (PMID 12695131, n=425) all reported significant hair gains at 1 mg/day, and a systematic review/meta-analysis (PMID 20956649, n=3927) pooled a consistent effect. This concordance is why the verdict is positive rather than neutral.
The grade stays at Preliminary rather than top-tier because the pivotal trials were industry-funded (a flagged conflict of interest) and regulators temper the picture. The US FDA approves finasteride but warns of sexual dysfunction that can persist after discontinuation; the UK NHS notes it does not work for everyone and is not NHS-funded for hair loss; and WHO pharmacovigilance data carry sexual-dysfunction safety signals.
Clinical bodies (Mayo Clinic, Harvard Health, the American Academy of Dermatology) back it as a first-line option for men, with Harvard citing 80-90% who maintain or regrow hair, while stressing that gains are lost within roughly a year of stopping. Crucially, this conclusion applies only to men: a trial in postmenopausal women found no benefit (PMID 11050579), and the female evidence is otherwise small and uncontrolled (PMID 16549704).
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 = 0.663
- 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