Short answer: In a 12-month trial that tested both, neither black cohosh nor red clover reduced hot flashes and night sweats more than placebo; only hormone therapy did.1 NIH says red clover has no conclusive benefit, and black cohosh may help overall menopause symptoms in a 2023 review but has rare liver injury reports.23
| Black cohosh | Red clover | |
|---|---|---|
| Plant | Root of a buttercup-family plant3 | A legume with isoflavones similar in structure to estrogen2 |
| Hot flashes over 12 months (Geller 2009) | 34% fewer; not better than placebo (63%)1 | 57% fewer; not better than placebo (63%)1 |
| Hormone therapy arm, same trial | 94% fewer, the only arm better than placebo1 | Same trial1 |
| NIH summary | 2023 review of 22 studies: potentially helpful for overall symptoms and hot flashes3 | No conclusive benefit; hot flash studies inconsistent2 |
| Safety | Rare liver damage reports; cause unproven3 | Used up to 2 years in studies with apparent safety2 |
| Pregnancy and breastfeeding | May not be safe3 | May be unsafe2 |
A four-arm, double-blind trial gave women standardized black cohosh, standardized red clover, placebo, or hormone therapy (conjugated estrogens plus medroxyprogesterone) for 12 months. Hot flashes and night sweats fell 34% on black cohosh, 57% on red clover, 63% on placebo and 94% on hormones; only hormones differed significantly from placebo. Both herbs were judged safe over 12 months.1
The placebo group improved a lot in this trial, which is why a placebo comparison matters. These are study protocols, not personalized advice; confirm any dosing with your prescriber.
Black cohosh: NCCIH says it has been used safely in studies lasting up to a year, but rare cases of liver damage, some very serious, have been reported with products labeled black cohosh; some contained the wrong herb. Black cohosh is not blue cohosh, which has serious risks. Its safety after breast or uterine cancer is uncertain.3
Red clover: extracts have been used in studies for up to 2 years and seem well tolerated.2
More detail: the Black Cohosh and Red Clover guides.