Black Cohosh for Hot Flashes
The best-quality clinical trials show that black cohosh does not reduce hot flashes any better than a placebo, and regulators have flagged a rare but serious risk of liver injury. It is not a reliable treatment for menopausal hot flashes.
Why this grade7-layer evidence engine
The grade is driven by the highest-quality evidence on hot flashes specifically. The 2012 Cochrane review (PMID 22972105, n=2027) found no difference from placebo in hot-flash frequency (a mean difference of just 0.07 flushes per day, p=0.79) and judged the evidence insufficient. The NIH-funded NCCTG Phase III trial (PMID 16782922, n=132) was even less encouraging: black cohosh was numerically worse than placebo (20% vs 27% reduction in hot-flash score, p=0.53).
A 2023 pooled meta-analysis (PMID 37192826) did report a small statistically significant benefit (Hedges' g = 0.315), but that signal came mainly from smaller, heterogeneous, and partly industry-sponsored trials of varying extract types and doses. It does not outweigh the consistent null results from the larger, rigorously designed placebo-controlled studies, especially given that placebo alone often cuts hot flashes by roughly 30%.
Mainstream sources reinforce this caution. The UK NHS states the supposed benefit is 'not supported by scientific evidence,' and Mayo Clinic notes that efficacy studies have had 'mixed results' alongside a rare possible link to liver damage. Harvard Health and menopause-specialty guidance advise against relying on it. Multiple regulators (UK MHRA, EU, and others) mandate liver-injury warnings, making the benefit-to-risk balance unfavorable for this non-life-threatening symptom.
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 = 0.393
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (2 篇 > 1 negative)
- 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