Cimicifuga racemosa or, as it is more commonly known, black cohosh, is a native American herb used primarily by women seeking relief from menopausal or menstrual disorders. The so-called “woman’s herb,” which is a member of the buttercup family, is prized in herbalism for the benefits of its rhizomes and roots.
How Does Black Cohosh Work?
Its effects in women were initially thought to be due to the presence of estrogenic compounds; however, they may be due in greater part to the herb’s serotonin receptor activators. A double-blind, randomized trial reported in 2002 found a lack of change in vaginal cytology measures or female hormone levels in women given black cohosh for 24 weeks, which suggests an absence of an overall estrogenic effect despite significant relief from menopausal symptoms in the majority of women who received either of two doses.2
What is Black Cohosh Used for?
Two early reviews concluded effectiveness and safety for black cohosh for the alleviation of menopausal symptoms, including hot flashes, profuse perspiration, sleep disturbances and depression.3,4 It has been suggested as an alternative for estrogen replacement therapy among women for whom hormone therapy is not recommended or for those who otherwise choose to forego it. Interestingly, a survey of 100 eligible women found that perceived quality of life was highest among women who used dietary supplements for menopause, including black cohosh, in comparison with those who used hormone replacement therapy, a combination of supplements and hormones, or no treatment.5
The Clinical Efficacy of Black Cohosh
A study of 20 women with menopausal complaints treated with 40 milligrams black cohosh daily for six months had a decrease in Kupperman’s Index values (which scores 11 menopausal symptoms) from an average of 30.2 points to 8.5 points after three months, which further decreased to 2.6 points after six months.6 No changes in hormone profiles or other biochemical values were observed. In a comparison of fluoxetine (PROZAC®) and black cohosh in 120 women with menopausal symptoms, Kupperman’s Index values were significantly lower after three months of treatment among the black cohosh group.7
Monthly hot flash and night sweat scores were also lower in comparison to those who received fluoxetine. At the end of six months, women who received black cohosh reported an 85% reduction in hot flash scores, compared to 62% in association with fluoxetine, leading the researchers to conclude that the herb was more effective for hot flashes and night sweats, while fluoxetine was better for depression.
In a randomized, double-blind trial that evaluated the effect of black cohosh in 48 postmenopausal women with sleep disturbance, the herb increased sleep efficiency and decreased wakefulness after sleep onset duration compared to a placebo.8
A meta-analysis of nine randomized trials of black cohosh for the treatment of menopausal complaints found significant improvements in comparison with a placebo in six trials and an overall 26% improvement in vasomotor symptoms.9
Does Black Cohosh Cause Cancer?
While the majority of research involving phytoestrogens has indicated an inhibitory effect against the growth of estrogen-responsive malignancies, a concern exists in regard to whether phytoestrogens could, in some cases, stimulate breast or other female cancers. An evaluation of four herbs used during menopause, one of which was black cohosh, failed to find estrogenic activity or stimulatory effects in cultured breast cancer cells.10
In fact, other research has shown that black cohosh antagonized estradiol-induced activities, indicating a possible protective effect against estradiol-fueled conditions.11 A study in estrogen receptor-positive and estrogen receptor-negative breast cancer cells found antiestrogenic activity in the former and growth inhibition in both cell lines.12 And in another study of estrogen receptor-positive and receptor-negative cells, black cohosh decreased growth and dose-dependently inhibited the conversion of estrone sulfate to estradiol, which is considered by some researchers to be the preferred pathway of estradiol synthesis in the breast.13
Black cohosh has also been demonstrated to suppress the invasiveness of estrogen-receptor negative human breast cancer cells.14
In a case-control study involving 949 women with breast cancer and 1,524 controls, women who used black cohosh had a 61% lower risk of breast cancer than those who did not report using the herb.15 In another study, none of the 65 women who completed a trial of daily black cohosh experienced an increase in mammographic breast density or experienced breast cell proliferation as ascertained by fine needle aspiration biopsies.16 And in a retrospective study of 18,861 breast cancer patients among whom 1,102 had used black cohosh extract, recurrence of the disease developed in 14% of nonusers after 2 years compared to 6.5 years among users.17
In a review of plant-based menopause treatments, a study in rats was cited which found that black cohosh extract was associated with many of the benefits of 17beta-estradiol, including effects in the brain, bone and urinary bladder, without causing uterine growth.18 The authors conclude that the extract “would appear as an ideal SERM (selective estrogen receptor modulator) and may therefore be an alternative to hormone replacement therapy.”
A study that involved 400 postmenopausal women with estrogen deficiency symptoms who were treated for a year with 40 milligrams black cohosh daily found a reduction in intensity and number of hot flashes and no incidence of increased endometrial thickness (which can occur when women consume unopposed estrogen).19
A one year randomized, double-blind, placebo-controlled trial that involved 351 women (the Herbal Alternatives for Menopause Study) concluded that black cohosh, used alone or as part of a multibotanical supplement with or without the addition of dietary soy, had no effects on the endometrium, vaginal epithelium or reproductive hormones.20
Nevertheless, if you have or have had breast, ovarian or endometrial cancer, it is suggested that you discuss the use of black cohosh with your physician.
The Bottom Line
Black cohosh is not just for perimenopausal and postmenopausal women. It can be used by younger women who have undergone surgical removal of their ovaries, and by those experiencing menstrual disorders.21 Its general ability to help relieve pain makes it useful for men as well.
- Ross SM. Holist Nurs Pract. 2007 May-Jun;21(3):162-3.
- Liske E et al. J Womens Health Gend Based Med. 2002 Mar;11(2):163-74.
- Liske E. Adv Ther. 1998 Jan-Feb;15(1):45-53.
- Lieberman S. J Womens Health. 1998 Jun;7(5):525-9.
- Kam IW et al. Menopause. 2002 Jan-Feb;9(1):72-8.
- Radowicki S et al. Ginekol Pol. 2006 Sep;77(9):678-83.
- Oktem M et al. Adv Ther. 2007 Mar-Apr;24(2):448-61.
- Jiang K et al. Climacteric. 2015;18(4):559-67.
- Shams T et al. Altern Ther Health Med. 2010 Jan-Feb;16(1):36-44.
- Amato P et al. Menopause. 2002 Mar-Apr;9(2):145-50.
- Zierau O et al. J Steroid Biochem Mol Biol. 2002 Jan;80(1):125-30.
- Garita-Hernandez M et al. Planta Med. 2006 Mar;72(4):317-23.
- Rice S et al. Maturitas. 2007 Apr 20;56(4):359-67.
- Hostanska K et al. In Vivo. 2007 Mar-Apr;21(2):349-55.
- Rebbeck TR et al. Int J Cancer. 2007 Apr 1;120(7):1523-8.
- Hirschberg AL et al. Menopause. 2007 Jan-Feb;14(1):89-96.
- Henneicke-von Zepelin HH et al. Int J Clin Pharmacol Ther. 2007 Mar;45(3):143-54.
- Wuttke W et al. Maturitas. 2003 Mar 14;44 Suppl 1:S9-20.
- Raus K et al. Menopause. 2006 Jul-Aug;13(4):678-91.
- Reed SD et al. Menopause. 2008 Jan-Feb;15(1):51-8.
- McKenna DJ et al. Altern Ther Health Med. 2001 May-Jun;7(3):93-100.