- Black cohosh (Actaea racemosa) is a medicinal herb.
- Current evidence does not support an association between black cohosh and increased risk of breast cancer.
- There is a lack of evidence supporting the efficacy of black cohosh for reduction of hot flashes in breast cancer patients.
- Black cohosh appears to be relatively safe; but pre-existing liver damage is a contraindication.
Black cohosh (Actaea racemosa, synonym: Cimicifuga racemosa) is a medicinal herb traditionally used by native American Indians for menstrual, menopausal, and other conditions. Extracts of black cohosh have been recommended as an alternative to hormone replacement therapy for the treatment of hot flushes in menopausal women.
The effects of black cohosh have been assessed in a systematic review including 14 randomized controlled trials, 7 uncontrolled trials and 5 observational studies. The evidence on efficacy forhot flushesis divided, with some benefits seen when compared with baseline, but not when compared with placebo. Two observational studies found no association between black cohosh and risk of breast cancer, whereas two studies reported significant reductions in risk of primary breast cancer among postmenopausal women and risk of recurrence, respectively. Seventeen trials showed no significant impact on circulating hormone levels or proliferation in oestrogen responsive tissues.
Reviews of preclinical and clinical studies suggest black cohosh to be safe but pre-existing liver damage is a contraindication.
Assessed as up to date in January 2019 by Barbara Wider.
Most recent update in March 2017 by Barbara Wider.
Assessed as up to date in September 2013 by Barbara Wider.
Update and revision in June 2012 by Jianping Liu, Xun Li and Guoyan Yang.
Fully revised and updated in August 2009 by Jianping Liu and Xun Li.
Summary first published in March 2006, authored by Jianping Liu.
Jianping Liu, Xun Li, CAM-Cancer Consortium. Black cohosh (Actaea racemosa) [online document]. March 9, 2017.
Black cohosh (Actaea racemosa, synonym: Cimicifuga racemosa) is a medicinal plant originating from eastern North America. Black cohosh products are commercially available on the market such as Remifemin® (manufactured by Schaper & Brümmer, Salzgitter, Germany) which is an isopropanolic extract of black cohosh standardised to contain 1 mg of triterpenes per 20 mg of extract1. Another standardised ethanolic extract of black cohosh is BNO 1055 (Menofem®/Klimadynon®), BIONORICA, Neumarkt, Germany)2.
The characteristic chemical constituents of the roots and rhizomes of black cohosh include cycloartenol-type triterpenoids and cimicifugoside, as well as cinnamic acid derivatives3.
Application and dosage
Black cohosh is a dietary supplement, usually available as tablets. The commonly used dosage for black cohosh is 40 to 80 mg of dried rhizome (root) daily.
Black cohosh has been used by native American Indians and Europeans for women’s conditions such as chronic ovaritis and amenorrhea4. It was first listed in the U.S. Pharmacopoeia in 1830 under the name “black snakeroot”5. It has been widely used for more than 40 years in Europe and was introduced in Germany in the 1940s for the treatment of menopausal discomfort, dysmenorrhoea, and climacteric neurovegetative complaints. More recently, black cohosh has been used as a therapy for menopausal symptoms such as hot flushes.
Claims of efficacy and alleged indications
Systemic breast cancer treatment can cause premature menopause, which results in hot flushes before the physiological menopause. Hot flushes are also the main adverse effect of the common anti-breast cancer treatment tamoxifen. Hormone replacement therapy (HRT) for hot flushes in breast cancer patients may not be appropriate because of evidence of a relationship between long-term use of HRT and increased risk of breast cancer and cardiovascular disease6, and potential stimulation of cancer growth by HRT7. There is therefore an increasing interest in finding safe and effective alternatives to HRT for the treatment of menopausal symptoms in breast cancer patients. Herbal preparations such as black cohosh are used as alternatives to HRT in the treatment of hot flushes8.
Mechanism of action
A systematic review including 21 pre-clinical studies concluded that there is a potential antiproliferative effect on breast and prostate tumour cells as well as a theoretical beneficial use in prostate cancer patients14. This is, however, not likely to be due to an estrogenic component of the herb as preclinical studies consistently conclude a lack of specific estrogenic activity. The antiproliferative effects, which are observed in in vitro and/or in vivo models for both breast and prostate cancer, are likely to be causally impacted by the favourable disruption of anti/pro-apoptotic cellular machinery.
An in vitro study investigating 9 herbal extracts and 23 isoflavonoids found strong inhibitory effect in extract of black cohosh on breast cancer resistance protein-mediated transport of methotrexate15. One animal study found that black cohosh presented some beneficial effect for breast cancer prevention and therapy, such as downregulating mitochondrial oxidative phosphorylation genes, but these findings were not consistent16. Another recent animal study found chemopreventive potentials for mammary cancer, as black cohosh was found reduce Ki-67 and cyclin D1 protein expression in fibroadenomas by immunohistochemistry17.
Prevalence of use
Specific prevalence data for the use of black cohosh by cancer patients are not available.
In most European countries and the US, plant-based preparations including herbal remedies are regulated as dietary supplements. However, the European Directive on traditional herbal medicinal products allows herbal medicines to be registered as drugs if they have been used medicinally for at least 30 years (including at least 15 years within EU countries)11. Black cohosh has been granted a traditional herbal registration by the Medicines and Healthcare products Regulatory Agency for the relief of symptoms of the menopause, such as hot flushes, night sweats, and temporary changes in mood12.
Cost(s) and expenditure
The average monthly cost of e.g. Remifemin is about US$20 or EUR11.
Fritz et al (2014) conducted a systematic review of black cohosh for use by pre- or postmenopausal breast cancer patients or those at risk of breast cancer13. A total of 26 articles were included: 14 randomized controlled trials (RCTs), 7 uncontrolled trials, and 5 observational studies. Impact on risk of primary breast cancer incidence, risk of breast cancer recurrence, effect on oestrogen responsive tissues, and efficacy in treating menopausal symptoms following breast cancer treatment were assessed.
Two observational studies found no association between black cohosh andrisk of breast cancer, whereas two studies reported significant reductions in risk of primary breast cancer among postmenopausal women (adjusted odds ratio = 0.47, 95% confidence interval = 0.27-0.82), andrisk of recurrence(adjusted hazard ratio = 0.75, 95% confidence interval = 0.63-0.89); in the latter study the results could have been influenced by higher tamoxifen use in the black cohosh group.
Seventeen trials (12 RCTs, 5 uncontrolled trials) showed no significant impact on circulatinghormone levels or proliferation in oestrogen responsive tissues.
The evidence from 3 RCTs, 2 uncontrolled trials and one observational study on efficacy forhot flashesis divided. Some benefits were reported when compared with baseline (2 uncontrolled trials, one RCT) but not when compared with placebo (2 placebo-controlled RCTs, one observational study).
An earlier review by Walji et al. (2007) of the safety and efficacy of black cohosh for cancer patients including five clinical studies also concluded that the research assessing efficacy of black cohosh for hot flushes associated with menopause in women with breast cancer was inconclusive; the existing results were conflicting and all the trials had significant methodological flaws14.
Controlled clinical trials
No additional clinical trials were identified.
No additional observational studies were identified.
The minor adverse effects observed in clinical studies include nausea, vomiting, headaches, dizziness, mastalgia, and weight gain18-20.
The above mentioned systematic review by Walji et al. of black cohosh in cancer patients concluded that black cohosh seems to have a relatively good safety profile14. Another systematic review of black cohosh’s safety in general (not only cancer patients) retrieved 13 clinical trials involving more than 2,800 patients21. All trials indicate relative safety: 97% of all the reported adverse effects were minor, and the only severe ones were not deemed to be related causally to black cohosh. This is in line with the findings of an earlier review22. Recent clinical trials in general populations confirm these findings23-26.
In response of the "potential association" between black cohosh and hepatotoxicity, a systematic review published in 2008 by the Dietary Supplement Information Expert Committee of the US Pharmacopeia's Council of Experts on the hepatotoxicity found all the reports of liver damage were assigned possible causality, and none were of probable or certain causality27. The clinical pharmacokinetic and animal toxicological information did not reveal unfavourable information about black cohosh.
Fritz et al did not systematically assess the impact of black cohosh on liver function but reported no impact on liver function or symptoms suggestive of impaired liver function among the studies the included in their review13.
A systematic review published in 2011 including five randomized double-blind clinical trials involving 1,117 women who were treated daily with black cohosh extract for 3 to 6 months also found no evidence that it had any adverse effect on liver function28. These confirms the findings of the 2007 systematic review by Walji including five RCTs and 21 pre-clinical studies of cancer patients13.
The eight most recent papers reviewing published and spontaneous case reports (numbers ranging from 22 to 75) of initially alleged black cohosh hepatotoxicity were identified. All surveys found a lack of causality for the herbal medicine in all cases29-36.
Pre-existing liver damage is a contraindication.
Black cohosh was found to alter the response to the agents commonly used to treat breast cancer in an experiment report using mouse breast cancer line37. In this experiment, the black cohosh extracts increased the cytotoxicity of doxorubicin and docetaxel and decreased the cytotoxicity of cisplatin.
Based on the safety review by the Dietary Supplement Information Expert Committee27, it was determined that black cohosh products should be labelled to include a cautionary statement. This is a change from the Expert Committee's decision of 2002, which required no such statement
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- Graf MC, Geller PA. Treating hot flushes in breast cancer survivors: a review of alternative treatments to hormone replacement therapy. Clin J Oncol Nurs 2003;7(6):637-40.
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- Fritz H, Seely D, McGowan J, Skidmore B, Fernandes R, Kennedy DA, Cooley K, Wong R, Sagar S, Balneaves LG, Fergusson D. Black cohosh and breast cancer: a systematic review. Integr Cancer Ther. 2014;13(1):12-29.
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- Wu XS. Remifemin improve gynecological malignant tumor postoperative patients of menopause syndrome for the clinical research. Dissertation for Master Degree of Dalian Medical University 2011; 1-20.
- Huang XF. The clinical research of Black cohosh extract in breast cancer patients with climacteric complaints. Dissertation for Master Degree of Manjing University of Chinese Medicine 2011;10-21.
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- Ross SM. Menopause: a standardized isopropanolic black cohosh extract (remifemin) is found to be safe and effective for menopausal symptoms. Holist Nurs Pract. 2012;26(1):58-61.
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- Sun NX, Jin ZJ, Jia XF, Li W. Black cohosh improves vaginal atrophy in postmenopausal women. Academic Journal of Second Military Medical University 2012;33(3): 339-42.
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- Naser B, Schnitker J, Minkin MJ, de Arriba SG, Nolte KU, Osmers R. Schaper & Brümmer GmbH & Co. KG, Salzgitter, Germany. Suspected black cohosh hepatotoxicity: no evidence by meta-analysis of randomized controlled clinical trials for isopropanolic black cohosh extract. Menopause. 2011;18(4):366-75.
- Teschke R, Schwarzenboeck A, Schmidt-Taenzer W, Wolff A, Hennermann KH. Herb induced liver injury presumably caused by black cohosh: a survey of initially purported cases and herbal quality specifications. Ann Hepatol. 2011;10(3):249-59.
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