Menopause symptom relief products remain big sellers in natural products stores. Black cohosh is an herb best known for treating these symptoms, particularly hot flashes. Currently, 40 million baby boomers are poised to enter menopause. As health-conscious consumers, these women want alternatives to the usual remedies. Conventional medicine typically offers hormone replacement therapies, which are naturally derived or synthetic hormones. They partially restore declining hormones during menopause, but they're often accompanied by undesired side effects or serious health concerns. The Women's Health Initiative study showed HRT can increase the risk of breast cancer, heart disease and stroke,1 prompting many women and health care practitioners to seek an effective alternative. The many years of European scientific research on the native North American black cohosh make it an increasingly popular option for health-minded medical practitioners and consumers.
Native American Roots
Black cohosh (Cimicifuga racemosa, now reclassified as Actaea racemosa)2 is a buttercup family member found in the eastern woodlands from southern Canada to the Deep South and west to Arkansas. It was called squaw root by the American Indians, suggesting it was used as a woman's tonic. Black cohosh was used by numerous native American Indian tribes, including the Winnebago, Penobscot, Delaware, Iroquois and Cherokee, for conditions such as arthritis, diarrhea and snake bites as well as coughs and other pulmonary conditions.3 It was a prominent herb in midwifery practice, employed to allay threatened miscarriage and to facilitate easy childbirth. It was also used for uterine prolapse and irregular menstruation. The Eclectic Physicians of the late 1800s valued its medicinal properties (it contains salicylic acid) for treating arthritis, nervous problems and pain after childbirth. The U.S. Pharmacopoeia recognized black cohosh as an official drug from 1820 to 1926.
Since the mid 1950s, results of at least 20 clinical trials of black cohosh involving more than 3,000 women show it can be more effective than placebo, and comparable to HRT, for relieving menopausal symptoms. All current human studies tested the brand Remifemin. A proprietary standardized black cohosh extract, Remifemin is widely used in Germany. Its popularity there is based on more than 40 years of clinical use and research showing it effectively reduces physical menopausal symptoms, including hot flashes, night sweats, headaches, heart palpitations, dizziness and vaginal atrophy, as well as psychological symptoms, including insomnia, depression, irritability and nervousness.
Researchers believe physical menopausal symptoms can be affected by increased levels of luteinizing hormones. Unlike estrogen, black cohosh can reduce luteinizing hormone levels, possibly through a direct action on the pituitary gland, but it has no effect on follicle stimulating hormone or prolactin.4,5
In a recent six-month controlled, randomized, double-blinded parallel group study, researchers confirmed a proprietary black cohosh extract did not demonstrate any systemic estrogenic effect, unlike HRT. Researchers gave perimenopausal and postmenopausal women either 39 mg or 127.3 mg of a unique black cohosh extract. There was no change in vaginal epithelium, luteinizing hormone or follicular stimulating hormone levels in subjects. Further, the higher dose was no more effective at reducing menopausal symptoms.6
In an open-label, uncontrolled study involving 629 women under the care of 131 doctors, researchers found Remifemin to effectively reduce menopausal symptoms in 80 percent of participants within six to eight weeks.7 Researchers also found the extract was safe and effective at relieving menopausal symptoms in a study of 40 women, all younger than 40 with at least one ovary, who'd had hysterectomies.8
A recent review of research on complementary and alternative medicine for menopausal symptoms included four black cohosh studies. All were controlled trials: one was placebo-controlled, one used both a treatment and placebo control, and two were treatment-controlled. Three of the four trials found black cohosh beneficial for treating hot flashes. The authors concluded, "There are no published data from human trials about the long-term safety, particularly regarding endometrial or breast stimulation. Effects on vaginal epithelium are inconclusive; two of the five randomized, controlled trials that examined estrogenic effect on vaginal epithelium reported a stimulatory effect. Although black cohosh may be useful for menopausal symptoms, long-term use cannot be presumed to be safe until appropriate safety studies are conducted."9
Researchers evaluating randomized clinical trials on Remifemin reported that the small beneficial effects observed in some studies could be explained by a central activity or an estrogenic activity. They concluded, "In spite of plausible mechanisms of action, C. racemosa's clinical efficacy for the treatment of menopausal symptoms has not been convincingly demonstrated through rigorous clinical trials." If the herb has an effect on menopausal symptoms, these researchers suggest it is attributable to an action separate from estrogen receptor activity. Additional research is warranted to test its efficacy, long-term safety, and to identify its pharmacologically active properties, they add.10
Black Cohosh Pharmacology
Researchers still aren't sure how black cohosh works. Since 1985, the plant's clinical actions have been attributed to the isoflavone formononetin. This constituent, however, was not found in extracts of black cohosh roots and rhizomes collected in 13 locations in the eastern United States. Remifemin does not contain the isoflavone, either. Therefore, the clinically observed estrogen-like actions of black cohosh, such as reduced hot flashes, are likely caused by a compound or combinations of compounds other than formononetin.11 In fact, studies show the herb has anti-estrogenic properties.12
Historic use and modern studies suggest black cohosh is a safe botanical, but as with all herbal products, it must be used appropriately. Side effects include minor stomach upset and headaches. Black cohosh has no known drug interactions, but should not be used during pregnancy or breast-feeding unless supervised by a qualified health professional.
Results of animal studies indicate black cohosh may potentiate the anti-estrogenic effects of tamoxifen.12,13 It is not contraindicated for women with breast cancer.14 Columbia University researchers evaluated the effect of Remifemin in a randomized clinical trial involving 85 patients diagnosed with breast cancer who had completed their primary treatment. The women were randomly assigned to black cohosh or placebo, stratified on tamoxifen use. Both the treatment and placebo groups had reduced intensity of hot flashes, but the differences between the groups were not statistically significant. Participants' levels of follicle-stimulating hormone and luteinizing hormone did not differ, either. Researchers concluded the herb was acceptable for use in such patients, but "black cohosh was not significantly more efficacious than placebo against most menopausal symptoms, including the number and intensity of hot flashes."15
Black cohosh has been used in Europe by more than 1.5 million women during the past 40 years. The German Commission E, a panel of medicinal plant experts commissioned by the German Health ministry in the 1970s, recommends limiting use to six months.9
Black cohosh, as Remifemin, was found to be most effective when used as a liquid extract or tablet rather than as a tea. The recommended dose as a tincture is 40 drops twice daily; as a fluid extract, 20 drops twice daily; or two standardized tablets (standardized to 4 mg triterpenes) twice a day. Because product strength can vary, it is best to follow label instructions. The German Commission E monographs recommend 40 mg of black cohosh daily to ease menopausal symptoms. One controlled, randomized, double-blind, parallel group study of peri- and postmenopausal women conducted during a 24-week period showed taking more than 40 mg a day did not increase effectiveness.6 There wasn't a placebo group in this trial, but the authors suggest black cohosh extract is associated with improvement in menopause symptoms without estrogen-like effects.
A Plant With Promise
Research to date indicates black cohosh, particularly Remifemin, is a safe and moderately effective alternative to estrogen replacement therapy for women who opt not to use synthetic HRT or for whom it is contraindicated. Support for black cohosh use is based on historical or anecdotal evidence, and research on the proprietary product, Remifemin. With so many women demanding safer alternatives to HRT, there is little doubt there will be more research on black cohosh. Meanwhile, traditional herbalists use the herb much as their forebears did.
Mindy Green, M.S., is an herbalist and author, and works for the University of Colorado Hospital Integrative Resource Center for Cancer in Denver. The author has no affiliations with black cohosh products or manufacturers.
1. Rossouw JE, et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the Women's Health Initiative randomized controlled trial. JAMA 2002 Jul 17;288(3):321-33.
2. Upton R. Black cohosh rhizome. Monograph by the American Herbal Pharmacopoeia, 2002.
3. Foster S. Black cohosh: for ease in menopause. The Herb Companion 1998 Aug-Sep:63-65.
4. Einer-Jensen N, et al. Cimicifuga and Melbrosia lack estrogenic effects in mice and rats. Maturitas 1996;25:149-53.
5. Amato P, et al. Estrogenic activity of herbs commonly used as remedies for menopausal symptoms. Menopause 2002 Mar-Apr;9(2):145-50.
6. Liske E, et al. Physiological investigation of a unique extract of black cohosh (Cimicifugae racemosae rhizoma): a 6-month clinical study demonstrates no systemic estrogenic effect. J Womens Health Gend Based Med 2002;11:163-74.
7. Stolze, H. An alternative to treat menopausal complaints. Gynakologie 1982;3(1):14-16.
8. Lehmann-Willenbrock E, Riedel HH. Clinical and endocrinologic examinations concerning therapy of climacteric symptoms following hysterectomy with remaining ovaries [in German]. Zentralblatt fur Gynakologie 1988;110:611-8.
9. Kronenberg F, Fugh-Berman A. Complementary and alternative medicine for menopausal symptoms: a review of randomized, controlled trials. Ann Int Med 2002 Nov 19;137(10):805-13.
10. Borrelli F, Ernst E. Cimicifuga racemosa: a systematic review of its clinical efficacy. Eur J Clin Pharmacol 2002 Jul;58(4):235-41.
11. Kennelly EJ, et al. Analysis of thirteen populations of black cohosh for formononetin. Phytomedicine 2002 Jul;9(5):461-7.
12. Zierau O, et al. Antiestrogenic activities of Cimicifuga racemosa extracts. J Steroid Biochem Mol Biol 2002 Jan;80(1):125-30.
13. Bodinet C, Freudenstein J. Influence of Cimicifuga racemosa on the proliferation of estrogen receptor-positive human breast cancer cells. Breast Cancer Res Treat 2002 Nov;76(1):1-10.
14. Lieberman S. Hormone replacement therapy and breast cancer risk. Alt Comp Ther 2002 Oct;8(5):262-6.
15. Jacobson JS, et al. Randomized trial of black cohosh for the treatment of hot flashes among women with a history of breast cancer. J Clin Oncol 2001 May;19:2739-45.
Natural Foods Merchandiser volume XXIV/number 3/p. 110, 112
Natural Foods Merchandiser volume XXIV/number 3/p. 112
Natural Foods Merchandiser volume XXIV/number 3/p. 112