Objective: The aim of this study was to evaluate the safety and efficacy of black cohosh and red clover compared with placebo for the relief of menopausal vasomotor symptoms.
Methods: This study was a randomized, four-arm, double-blind clinical trial of standardized black cohosh, red clover, placebo, and 0.625 mg conjugated equine estrogens plus 2.5 mg medroxyprogesterone acetate (CEE/MPA; n = 89). Primary outcome measures were reduction in vasomotor symptoms (hot flashes and night sweats) by black cohosh and red clover compared with placebo; secondary outcomes included safety evaluation, reduction of somatic symptoms, relief of sexual dysfunction, and overall improvement in quality of life.
Results: Reductions in number of vasomotor symptoms after a 12-month intervention were as follows: black cohosh (34%), red clover (57%), placebo (63%), and CEE/MPA (94%), with only CEE/MPA differing significantly from placebo. Black cohosh and red clover did not significantly reduce the frequency of vasomotor symptoms as compared with placebo. Secondary measures indicated that both botanicals were safe as administered. In general, there were no improvements in other menopausal symptoms.
Conclusions: Compared with placebo, black cohosh and red clover did not reduce the number of vasomotor symptoms. Safety monitoring indicated that chemically and biologically standardized extracts of black cohosh and red clover were safe during daily administration for 12 months.
Both black cohosh and red clover are widely used as over-the-counter botanical treatments for menopausal symptoms. In this phase II clinical trial, black cohosh and red clover did not significantly reduce the frequency of vasomotor symptoms as compared with placebo.
From the 1Department of Obstetrics and Gynecology, Center for Research on Women and Gender, College of Medicine, University of Illinois at Chicago, Chicago, IL; 2Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, IL; 3University of Illinois at Chicago/National Institutes of Health Center for Botanical Dietary Supplements Research, College of Pharmacy, University of Illinois at Chicago, Chicago, IL; and 4Department of Mathematics, Statistics and Computer Science, University of Illinois at Chicago, Chicago, IL.
Received February 18, 2009; revised and accepted May 5, 2009.
Funding/support: This study by the University of Illinois at Chicago/National Institutes of Health Center for Botanical Dietary Supplements Research was supported by National Institutes of Health Grant P50 AT000155 funded jointly by the Office of Dietary Supplements, the National Center for Complementary and Alternative Medicine, the National Institute for General Medical Sciences, and the Office for Research on Women's Health.
The contents are solely the responsibility of the authors and do not necessarily represent the views of the funding agencies.
Clinical Trials Registration Number: NCT00066144.
Financial disclosure/conflicts of interest: During the course of these studies, Norman R. Farnsworth was a paid consultant to Pharmavite.
Address correspondence to: Stacie E. Geller, PhD, Department of Obstetrics and Gynecology, Center for Research on Women and Gender, College of Medicine, University of Illinois at Chicago, 820 S. Wood Street (M/C 808), Chicago, IL 60612. E-mail: firstname.lastname@example.org