Black cohosh
Summary
For menopausal hot flashes, a 2012 Cochrane review of 16 trials (2,027 women) found no difference vs placebo in flush frequency, and two 12-month US trials at 128–160 mg/day agree (no effect). A 2010 meta-analysis that included combination products found a 26% improvement. At least 83 liver-injury reports exist, without proven causation.
Key facts
- Root and rhizome extract of Actaea racemosa; products vary widely in composition[1]
- Hot flash frequency and menopausal symptom scores: no difference vs placebo in single-herb trials (no effect)[2][3][4]
- None set; black cohosh is not a nutrient[1]
- No clinically relevant interactions known, though not systematically studied[1]
- Mild, short-lived stomach upset and rash; rare liver-injury reports[1]
- 3 graded human outcomes on this page
- October 10, 2026
How it works
ProposedHow black cohosh might work is unknown. Studies disagree on whether it has estrogen-like effects; researchers have proposed actions on serotonin pathways in the brain, antioxidant effects, or selective estrogen-receptor activity.[1]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Hot flash frequency and menopausal symptom scores | No effect | No effect | Systematic review · n = 2,027 · 2012 Perimenopausal and postmenopausal women in 16 RCTs Form: oral black cohosh single-herb preparations · Dose: Median 40 mg/day (8–160 mg/day) · Duration: Mean 23 weeks No difference vs placebo in daily hot flushes (MD 0.07 per day; 3 trials, 393 women) or symptom scores (4 trials, 357 women). Hormone therapy did better than black cohosh. Authors found insufficient evidence to support or oppose use. | 22972105 (opens PubMed)Source [2] |
| Hot flashes and night sweats | No effect | No effect | RCT · n = 351 · 2006 Women aged 45–55 with 2 or more hot flashes or night sweats a day (Washington State) Form: black cohosh 70% ethanolic extract, 2.5% triterpene glycosides · Dose: 160 mg/day · Duration: 12 months Hot flashes and night sweats per day and their intensity did not differ from placebo at 3, 6 or 12 months; hormone therapy cut about 4 symptoms per day vs placebo. | 17179056 (opens PubMed)Source [3] |
| Hot flashes and night sweats | No effect | No effect | RCT · n = 89 · 2009 Perimenopausal and postmenopausal women with 35 or more hot flashes and night sweats a week Form: black cohosh 75% ethanolic extract, 5.7% triterpene glycosides · Dose: 128 mg/day · Duration: 12 months Symptoms fell in all groups, but black cohosh and red clover did not differ from placebo; symptom intensity was worse with black cohosh at 6 and 9 months. | 19609225 (opens PubMed)Source [4] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Isopropanolic root extract (for example Remifemin, equivalent to 40 mg root per day) | Varies[1] | No human absorption data in our sources.[1] | Low incidence of mild side effects in trials.[1] | Menopausal symptoms (the Cochrane median dose) |
| Ethanolic extract standardized to triterpene glycosides | Varies[1] | No human absorption data in our sources.[1] | Used for 12 months at 128–160 mg/day in two US trials.[3][4] | Menopausal symptoms (null in US trials) |
| Powdered whole root | Varies[1] | No human absorption data in our sources; composition varies.[1] | No form-specific data.[1] | Not the form used in most trials |
Studied doses
Doses studied in human trials ranged from 8 to 160 mg/day of black cohosh extract, with a median of 40 mg/day, for 8 to 54 weeks. Extracts differ, so milligrams are not equal across products.[1][2]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Liver disorders
- At least 83 cases of liver damage have been reported with black cohosh worldwide, without proven causation. The US Pharmacopeia advises people with liver disorders to avoid it and anyone who develops abdominal pain, dark urine or jaundice to stop and see a clinician.[1][6]
- Pregnancy
- The American Herbal Products Association advises against use in pregnancy except under clinician supervision, because it has not been rigorously studied.[1]
- Long-term use
- Most trials lasted 6 months or less; long-term safety has not been studied.[1]
- Medicines
- No clinically relevant drug interactions are known, but they have not been systematically studied.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Liver safety
Liver injury is rare but is the most serious concern raised for black cohosh.
- Case reports
- A 2021 case report describes cholestatic liver injury in a 50-year-old woman, which resolved over 6 months after she stopped black cohosh.[6]
- Causality is uncertain
- Some reported cases may reflect impurities, adulterants or the wrong Actaea species; the products were not independently analysed.[1]
- Label warnings
- Australia has required a liver warning on black cohosh products since 2007; the US FDA does not require one.[1]
How to read the label
- Label dose vs clinical doseThe Cochrane trials used a median 40 mg/day of extract (8–160 mg/day). A label listing hundreds of milligrams of root powder is not comparable to an extract dose.[1][2]
- Check the extract typeTrials used isopropanolic or ethanolic root extracts, sometimes standardized to triterpene glycosides; extracts are frequently standardized to at least 1 mg triterpene glycosides per daily dose.[1]
- Look for the species nameLiver-injury reports may involve the wrong Actaea species, so the label should name Actaea (Cimicifuga) racemosa root.[1]
Frequently asked questions
Does black cohosh work for hot flashes?
The best evidence says not reliably. A Cochrane review of 16 trials found no difference from placebo in hot flash frequency, and two 12-month US trials also found no benefit. A 2010 meta-analysis that pooled combination products found a 26% improvement.[2][3][4][5]
How much black cohosh was used in studies?
Between 8 and 160 mg/day of extract, with a median of 40 mg/day, for 8 to 54 weeks.[1][2]
Is black cohosh bad for your liver?
At least 83 liver-injury cases have been reported, but no causal link is proven. The US Pharmacopeia advises stopping if you develop abdominal pain, dark urine or jaundice.[1][6]
Is black cohosh as effective as hormone therapy?
No. In trials, hormone therapy reduced hot flashes and symptom scores more than black cohosh.[2][3]
Does black cohosh act like estrogen?
It is unclear. Studies disagree on whether it raises estrogen or changes vaginal and uterine tissue.[1]
What do menopause societies say about black cohosh?
ACOG concluded that data do not show herbal supplements such as black cohosh are effective for hot flashes, and the North American Menopause Society calls them unlikely to help.[1]
Sources
- [1]Black Cohosh: Fact Sheet for Health Professionals (updated June 3, 2020). NIH Office of Dietary Supplements, 2020. fact-sheet
- [2]Black cohosh (Cimicifuga spp.) for menopausal symptoms.. Cochrane Database Syst Rev, 2012. systematic-review
- [3]Treatment of vasomotor symptoms of menopause with black cohosh, multibotanicals, soy, hormone therapy, or placebo: a randomized trial.. Ann Intern Med, 2006. RCT
- [4]Safety and efficacy of black cohosh and red clover for the management of vasomotor symptoms: a randomized controlled trial.. Menopause, 2009. RCT
- [5]Efficacy of black cohosh-containing preparations on menopausal symptoms: a meta-analysis.. Altern Ther Health Med, 2010. meta-analysis
- [6]Case of cholestatic drug-induced liver injury (DILI) associated with black cohosh.. BMJ Case Rep, 2021. observational
What changed
- First draft. Every PMID checked against NCBI E-utilities esummary (title and year taken from the record) and abstracts read for the cited rows.
- Adversarial review pass: claims checked against the Cochrane abstract, the HALT trial abstract and the NIH ODS fact sheet; the 2010 positive meta-analysis kept in text only (pooled n not reported) and flagged as including combination products. Page set indexable.
- Second review: Geller 2009 sample corrected to 89 randomized women (full text, PMC2783540).