Black Cohosh
A popular menopause herb with mixed evidence for hot flashes and rare reports of liver injury.
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What it is
Black cohosh is an extract from the root of a North American plant in the buttercup family. It was traditionally used by Indigenous peoples for women's health and is now one of the most popular herbs for menopause.
How it works
Black cohosh was once thought to act like a plant estrogen, but more recent research suggests it doesn't behave like estrogen in the body. It may act on serotonin and other brain pathways involved in temperature regulation. The mechanism remains uncertain, which fits with the inconsistent trial results.
What it's been studied for
Commonly taken for menopausal hot flashes, night sweats, and mood changes.
What the evidence shows
Evidence is mixed: some European trials of specific standardized extracts reported improvement in hot flashes, but a well-designed year-long NIH-funded trial found black cohosh no better than placebo. A Cochrane review concluded there's insufficient evidence to support its use for menopausal symptoms. The key limitation is inconsistent results across studies that used different extracts, doses, and outcome measures.
Who should consider it
Women with bothersome hot flashes who can't or prefer not to use hormone therapy may reasonably consider a trial, with realistic expectations and their provider's input. People with liver disease, anyone pregnant or breastfeeding, and people with a history of hormone-sensitive cancer should avoid it unless their provider approves. Those with severe symptoms have well-studied medical options that are worth discussing.
Amounts commonly studied
Studies typically used about 40 to 160 mg per day of a standardized root extract (often 20 to 40 mg twice daily), for periods of 3 to 12 months.
How to take it
Studies typically used a standardized extract once or twice daily with food, and most trials lasted 3 to 12 months. If there's no improvement after a couple of months, it's unlikely to help. Talk to your provider before starting, and stop immediately if you notice any signs of liver trouble.
Forms & absorption
Standardized extracts in tablets or capsules are the most studied forms; teas and tinctures vary in strength. Product quality matters, as some black cohosh products have been found to contain other species.
Food sources
None — black cohosh is a medicinal root (Actaea racemosa), not a dietary food, and is taken only as a supplement.
Safety & interactions
Usually well tolerated; stomach upset, headache, and rash can occur. Rare cases of serious liver injury have been reported, so people with liver disease should avoid it, and anyone taking it should stop and seek care if they develop dark urine, yellowing of the skin or eyes, abdominal pain, or unusual fatigue. Avoid it during pregnancy and breastfeeding, and talk to your provider first if you have a history of breast cancer or other hormone-sensitive conditions or take medications that can affect the liver.
Myths & what it won't do
Myth: black cohosh is a natural estrogen replacement. Reality: current research suggests it doesn't act like estrogen, and it hasn't consistently outperformed placebo for hot flashes. Myth: black cohosh and blue cohosh are interchangeable. Reality: they're unrelated plants, and blue cohosh carries more serious safety concerns.
Common questions
- Does black cohosh work for hot flashes?
- Results are mixed. Some trials of specific extracts found benefits, but a well-designed year-long trial and a Cochrane review didn't find convincing evidence it beats placebo.
- Is it safe for my liver?
- Serious liver injury is rare, but it has been reported. Avoid it if you have liver disease, and stop and see your provider if you notice dark urine, yellowing of the skin or eyes, or abdominal pain.
- Can I take it if I've had breast cancer?
- Talk to your oncologist first. The data on safety after breast cancer are limited, and your care team can weigh it against other options.
The amounts listed here are what published research has used — not a prescription or a recommended dose for you. Confirm anything you plan to take with your own healthcare provider, especially if you take medications, are pregnant or nursing, or have a health condition.
Related goals
Research on Black Cohosh
Recommendations on this page are informed by published research. This is educational information, not medical advice.
- Leach MJ, Moore V. Black cohosh (Cimicifuga spp.) for menopausal symptoms. Cochrane Database Syst Rev. 2012;(9):CD007244. View study →Note: Across 16 trials (2,027 women), black cohosh was no better than placebo for hot flashes; evidence was insufficient to support its use.
- Newton KM, Reed SD, LaCroix AZ, et al. Treatment of vasomotor symptoms of menopause with black cohosh, multibotanicals, soy, hormone therapy, or placebo: a randomized trial. Ann Intern Med. 2006;145(12):869-879. View study →Note: In a year-long trial, black cohosh and other herbal approaches were no better than placebo for hot flashes and night sweats.