Black Cohosh
Black cohosh (Actaea racemosa) is a plant of the buttercup family from North America. Its root and rhizome are used in herbal preparations.
Also listed as Cimicifuga racemosa, Bugbane, Bugroot, Snakeroot
What it is studied for
The strongest rated effects first. Bars show the size of the effect, the letter grades the evidence, and each rating lists the studies behind it.
What is black cohosh?
Black cohosh (Actaea racemosa, also called Cimicifuga racemosa) is a member of the buttercup family that grows in North America. The root and rhizome (the underground stem) are used in herbal preparations. 1 2
Native Americans used it for conditions such as kidney ailments, sore throat and menstrual cramps. It has been used medicinally in Germany since the late 19th century and today is mainly promoted for menopause symptoms. 1
In the EU, black cohosh extracts are regulated as herbal medicinal products for menopausal complaints, based on well-established use. In the US they are sold as dietary supplements, which do not need FDA approval before sale. 1 2 3
What is in black cohosh?
The root contains at least 40 triterpene glycosides, including actein and 23-epi-26-deoxyactein, which is specific to black cohosh and often used to standardize products. It also contains phenolic acids such as fukinolic acid and a range of alkaloids that have hardly been studied biologically. 2
How might black cohosh work?
The European Medicines Agency states that neither the mode of action nor the constituents responsible for relief of menopausal complaints are known. 4
Black cohosh was long assumed to act like estrogen. The hydroalcoholic extracts used in most clinical products generally show no estrogenic activity in laboratory and clinical studies, while lipophilic extracts do affect estrogen-regulated genes in lab tests. 2
In a 6-month randomized trial in women around menopause, two doses of an isopropanolic extract did not change vaginal cytology or hormone levels. Another trial reported a weak estrogen-like effect on the vaginal lining but none on the endometrium. 5 6
Other hypotheses involve serotonin and the brain's own opioid system. In a small study of postmenopausal women, blocking opioid receptors with naloxone changed hormone responses during black cohosh treatment, which the authors read as central opioid activity. 2
What is black cohosh mainly studied for?
Most human research concerns hot flashes and other menopausal symptoms, including in women treated for breast cancer. Smaller bodies of research cover sleep, mood, bone markers and fertility in polycystic ovary syndrome. Much less research exists for other uses, and the research tab takes each question separately. 1 2 7
Key studies
The most recent publications linked to Black Cohosh's ratings.
Why people take it
SuppCo community snapshot, 2026-09-28. Reasons for use are not evidence that it works.
Questions people ask
Does black cohosh work for hot flashes?
The evidence is mixed. Some pooled analyses and the German IQWiG report find a modest benefit for standardized extracts, while a Cochrane review and a one-year US trial found no clear difference from placebo. Hormone therapy works better. 7 8 9 10
Is black cohosh a natural estrogen?
Probably not. The extracts used in clinical products did not change estrogen or other sex hormone levels in trials and showed no estrogen-like effect on breast or endometrium. How it works is not known. 2 4 5
Is black cohosh bad for the liver?
Rare cases of serious liver injury have been reported, though it is uncertain whether black cohosh itself caused them; wrong or mixed plants in products may play a role. Stop and see a doctor if you notice yellow skin or eyes, dark urine or unusual tiredness. 1 2 4
Can I take black cohosh after breast cancer?
Observational studies found no higher cancer or recurrence risk, but the EU monograph advises against use without medical advice after breast cancer or other hormone-dependent tumors, and NCCIH calls the safety uncertain. 1 2 4
How long can black cohosh be taken?
Studies have run for up to about a year. The EU monograph says not to take it for more than 6 months without medical advice. 1 4
Is black cohosh the same as blue cohosh?
No. Blue cohosh is a different plant with different risks, including high blood pressure and serious complications in newborns when used to induce labor. 1
Sources
- Black Cohosh: Usefulness and Safety (last updated November 2024) National Center for Complementary and Integrative Health (NCCIH), 2024
- Black Cohosh (PDQ), Health Professional Version (updated 10/31/2024) National Cancer Institute, 2024
- Cimicifugae rhizoma: herbal medicinal product (summary for the public) European Medicines Agency, 2018
- European Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma (EMA/HMPC/48745/2017) European Medicines Agency, Committee on Herbal Medicinal Products, 2018
- Physiological investigation of a unique extract of black cohosh (Cimicifugae racemosae rhizoma): a 6-month clinical study demonstrates no systemic estrogenic effect Journal of Women's Health & Gender-Based Medicine (Liske et al.), 2002 · Study record
- Effects of black cohosh (Cimicifuga racemosa) on bone turnover, vaginal mucosa, and various blood parameters in postmenopausal women: a double-blind, placebo-controlled, and conjugated estrogens-controlled study Menopause (Wuttke et al., Universität Göttingen), 2006
- Black cohosh extracts in women with menopausal symptoms: an updated pairwise meta-analysis Menopause (Sadahiro et al.), 2023 · Study record
- Cimicifuga: Evidenzbericht zur S3-Leitlinie Peri- und Postmenopause, Diagnostik und Interventionen (IQWiG-Berichte Nr. 1923) Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen (IQWiG), 2025
- Black cohosh (Cimicifuga spp.) for menopausal symptoms Cochrane Database of Systematic Reviews (Leach & Moore), 2012 · Study record
- Treatment of vasomotor symptoms of menopause with black cohosh, multibotanicals, soy, hormone therapy, or placebo: a randomized trial Annals of Internal Medicine (Newton et al.), 2006