Black Cohosh and Climacteric Symptoms: Growing Knowledge about the Efficacy and Safety

Abstract

Hormone therapy of perimenopausal and postmenopausal disorders includes, in many cases, treatment with estrogens but many recent studies have raised the question as to whether it brings more dangers than benefits for patients. This has led to an increased use of alternatives, mainly plant derived extracts. Among the botanical supplements and herbal medicinal products, extracts of the rhizome and roots of black cohosh are used worldwide for these purposes. This plant has a long-standing history of being used to treat climateric complaints and its clinical efficacy has been proven in several double-blind placebo controlled studies. In terms of safety, minor and transient adverse effects such as nausea, vomiting, headaches and dizzness have been observed in clinical trials. A few cases of hepatotoxicity have been reported, but a direct association with the use of black cohosh has not been demonstrated. Black cohosh was first thought to be estrogenic in nature, but recent studies have proposed it as selective estrogen receptor modulator (SERM) and serotoninergic, dopaminergic and cholinergic mechanisms have been described. Black cohosh shows great promise for relief of menopausal symptoms, primarly of vasomotor and possibly mood symptoms, with an overall positive safety profile of at least 6 months and likely longer. However, data from longer and in some cases more rigorous clinical trials are necessary to assess high efficacy and to substantiate safety.