Do black cohosh (Actaea racemosa) or red clover (Trifolium pratense) reduce menopausal symptoms such as hot flushes and night sweats in menopausal women?

Black cohosh (Actaea racemosa) has shown a statistically significant effect on hot flushes in a meta-analysis of 22 randomised placebo-controlled studies involving 2,310 women. The effect is moderate in size (Hedges' g = 0.315). The effect on total menopausal symptoms, including somatic complaints such as night sweats, is larger (Hedges' g = 0.575). These represent multiple independent human studies, so this is not a single isolated finding.

The specific isopropanolic form of black cohosh (iCR, the most extensively studied standardised form) was compared with placebo in a large systematic review covering 35 clinical studies with nearly 44,000 women. The benefit was significant and comparable to that of a low-dose transdermal oestrogen. Importantly, hormone levels and oestrogen-sensitive tissues, such as breast and endometrium, remained unchanged. No evidence of liver toxicity was found. That said, some guidelines recommend caution due to lingering uncertainty about dosage and preparation in non-standardised products.

Black cohosh has shown no proven effect on anxiety or depressive symptoms. In the same meta-analysis, the effects on mood and anxiety were not statistically significant. Women experiencing mood-related symptoms during menopause should therefore not expect much benefit from black cohosh.

Red clover (Trifolium pratense, isoflavones) has a much weaker evidence base in the available studies. None of the primary studies provided examined red clover separately for hot flushes or night sweats. Review articles and clinical guidelines describe red clover as controversial: its efficacy and safety have not been well established, and the appropriate dosage and preparation remain unclear. On the basis of the available sources, it cannot therefore be concluded that red clover is effective for menopausal symptoms.

Combination preparations containing black cohosh alongside soy isoflavones, lignans, or chasteberry showed substantial improvements in hot flushes, night sweats, and sleep in two smaller RCTs (90 and 101 women). However, because these are combination products, it is not possible to determine which component is responsible for the effect. In practice, this means those studies cannot be used to make claims about red clover or soy isoflavones in isolation.

In terms of safety, standardised black cohosh appears to be well tolerated: dropout due to side effects does not differ from placebo, and large safety analyses found no liver toxicity. Side effects are rare and no known drug interactions have been reported. Anyone using a non-standardised product has less certainty about dosage and composition, and some degree of caution remains appropriate in that case.