The alcoholic extract of black cohosh root is widely used by women in Europe and now the USA as a treatment for menopausal symptoms.54-56 Virtually all of the clinical studies have been done with one preparation, Remifemin, originally developed in Europe and now marketed in the USA. Many men with prostate cancer on hormonal therapy are using Remifemin or other black cohosh root preparations as treatment for their hot flashes and other symptoms of male menopause.
Black cohosh was one of the medicinal plants widely used by various American Indian tribes and adapted by early European settlers as a treatment for rheumatism. The use of black cohosh for menopausal symptoms became widespread during the 1800s in both America and Europe. At present, virtually all significant clinical and laboratory investigation on black cohosh have been performed by European investigators. Numerous clinical trials, including randomized controlled trials, have compared Remifemin with placebo and a variety of estrogen preparations commonly used as hormone replacement therapy for women. It is now well documented that this herbal preparation effectively reduces hot flashes in women. Remifemin also appears to be effective in countering the depression, insomnia and other psychiatric complications of female menopause. In addition, this black cohosh extract appears to prevent bone loss in animals after surgical removal of the ovaries, raising the possibility that it might also ameliorate the development of osteoporosis. This possibility has yet to be tested in humans. Remifemin also appears to act on the female genitalia, where it has been reported to cause estrogen-like effects on the vaginal mucosa.
The production of estrogen by the ovary is stimulated by luteinizing hormone (LH). When the brain senses that sufficient estrogen is present, it decreases the production of LH, shutting down the production of additional estrogen.57 During menopause in women, LH production increases because the brain senses the absence of estrogen. The magnitude of this LH rise has been reported to correlate with the severity of menopausal symptoms. A majority of the studies indicate that a dose of Remifemin sufficient to reverse menopausal symptoms also blocks the release of LH.
As with most herbal preparations, Remifemin is composed of a mixture of different chemicals. Fractions have been identified that can bind to the estrogen receptor and appear to mimic the actions of estrogen. Another fraction can block LH release even though it has no estrogenic activity. These results suggest that it would be possible to prepare black cohosh extracts that selectively suppress the response of the brain to menopause, such as hot flashes, depression and insomnia, that lack any activity at the estrogen receptor.
The most common side effect of Remifemin is transient gastric distress seen in approximately 7% of women. In fact, it seems to be as well or better tolerated than the commonly used estrogenic medications. In particular, it appears to be much less likely to cause uterine bleeding. In standard test systems, it also does not cause mutations or stimulate the development of cancers. This is important because naturally occurring estrogens may promote the development of cancers of the breast and uterus.
What about the use of Remifemin and other black cohosh extracts in men? There are no clinical trials in which Remifemin or other black cohosh extracts were administered to men. In men already on hormonal therapy, the estrogenic activity of this supplement may cause breast enlargement and other estrogen-dependent side effects. We have no information about the impact of Remifemin and other black cohosh preparations on prostate cancer growth and spread, and it is impossible to predict its impact on this disease. Therefore, its use in men is questionable at best until we have a better understanding of its impact on the physiology of the human male and its effects on prostate cancer.
Was this article helpful?