Black cohosh (Actea racemosa, or Cimicifuga racemosa) is an herbaceous perennial plant that has undergone extensive research for its clinical benefits to women's health. Clinical studies reveal that black cohosh may support women experiencing complaints associated with the menopausal transition, such as hot flashes, sleep disturbances, and mood swings. 

Native to eastern and central North America, black cohosh belongs to the Ranunculaceae family. Approximately 131 compounds have been identified in this herb. Key constituents of black cohosh include triterpene glycosides, phenols, flavonoids, and alkaloids. It is known by various names, such as bugbane, rattle weed, snakeroot, and squaw root.

For centuries, Europeans have used black cohosh to help promote menopausal comfort. Previous research indicates that black cohosh might influence estrogen metabolism, acting as both an estrogen agonist and antagonist in certain tissues due to an isoflavone called formononetin. However, recent studies have challenged this proposed mechanism due to various analytical techniques being unable to identify the formononetin compound in black cohosh in separate experiments. 

Instead, studies propose that the benefits of black cohosh stem from its effects on neurotransmitter production, including serotonin, dopamine, GABA, and µ-opioid, which influence thermoregulation, mood, and sleep. For instance, triterpene glycosides (a major constituent of black cohosh) may play a role in serotonin regulation, which is relevant to menopausal-associated hot flashes as it affects thermoregulation in the hypothalamus. 

A meta-analysis of 22 randomized controlled trials involving 2,310 menopausal women assessed the effects of black cohosh extract, alone or in combination with other active ingredients. Women who received black cohosh extract experienced significant improvements in overall menopausal symptoms compared to the placebo groups, including reductions in hot flashes and somatic symptoms. Notably, black cohosh did not significantly reduce anxiety or depressive symptoms. On the other hand, a systematic literature search encompassing 35 clinical studies and one meta-analysis with 43,759 women (including 13,096 who received black cohosh extract) revealed that women who were administered black cohosh extract experienced significantly improved psychological menopausal symptoms, including improved mood, compared to a placebo. 

Moreover, black cohosh may potentially support postmenopausal bone strength, as demonstrated in ovariectomized rat models. In vitro studies indicate that the major triterpenes in black cohosh mitigate the effects of oxidative damage on osteoblasts. The triterpenes may also promote increased cell growth, collagen content, alkaline phosphatase activity, and mineralization, potentially supporting overall bone strength.

Lastly, a randomized, double-blind, placebo-controlled clinical trial involving 42 postmenopausal women aged 45 to 60 compared black cohosh and a placebo on sleep quality. Compared to the placebo, those taking black cohosh experienced significant improvements in polysomnographic measures, including increased sleep efficiency and reduced wake-after-sleep onset duration (15.8% reduction). They also exhibited an improved PSQI (Pittsburg Sleep Quality Index) score, showing a medium-sized effect.

Black cohosh has a long history of use in supporting women’s health. It may help diminish common menopausal complaints, such as mild hot flashes, sleep disturbances, unbalanced mood, and dysregulated bone strength, and, therefore, may be clinically beneficial for menopausal women. 

By Danielle Moyer, MS, CNS, LDN