Research on black cohosh primarily focuses on its potential benefits for perimenopause and postmenopause symptoms.
One meta-analysis revealed that the isopropanolic extract of black cohosh (iCR) was found to be more effective than placebo in alleviating neurovegetative symptoms (e.g., hot flashes, night sweats, palpitations) and psychological symptoms (e.g., depression) in women with natural perimenopausal and postmenopausal symptoms.[1] One of the studies within this meta-analysis also found that black cohosh improved sleep efficiency and decreased wake after sleep onset (WASO) compared to placebo.[2]
For women undergoing iatrogenic menopause (i.e., menopause brought about by medical interventions such as hysterectomy), the effects of black cohosh are inconsistent. In one placebo double-blind RCT menopausal women with breast cancer (many undergoing tamoxifen treatment) who received iCR for 2 months did not exhibit a significant reduction in the intensity and count of hot flashes compared to placebo. However, they reported notably-reduced night sweating.[3] It’s important to note that this study suffered from a small sample size and a high dropout rate, with hot flashes being self-reported by the participants. That said, longer-duration open studies (12–24 weeks) also have demonstrated significant reductions in induced hot flashes, sweating, and psychological symptoms in participants taking iCR.[1]
To validate these findings, more extended RCTs that assess climacteric symptoms (i.e., symptoms of perimenopause, menopause and/or postmenopause) using objective measurements[4] (e.g., increases in heart rate, finger blood flow, respiratory exchange ratio, skin temperature, and core body temperature) instead of self-reported questionnaires are essential.