Educational information, not medical advice — ask your doctor or midwife.
Actaea racemosa, or black cohosh, is a woodland plant from eastern North America. The dried root and rootstock are sold as a supplement. People take it mainly for hot flushes and night sweats around menopause.
It is not a food and not a hormone. It is a root extract, sold as tablets, capsules, drops and tea.
The short evidence verdict: human results are mixed and mostly weak. Some trials show a small drop in hot flushes. Others show nothing beyond placebo, and long use by healers does not prove it works or that it is safe.
No one knows how black cohosh works.
It was once sold as a plant oestrogen. Most laboratory work does not support that idea. In cell studies the root extract binds poorly to oestrogen receptors.
Other ideas come from lab and animal work. In those settings, parts of the root appear to act on serotonin receptors, which help control body heat. Some animal work also points to opioid receptors.
Whether any of this happens in a woman taking a capsule is not established. The gap between a lab dish and a person is wide here.
Black cohosh is sold as a root preparation, in several forms.
Common forms: - Tablets and capsules of standardised root extract - Tinctures and liquid drops made with alcohol - Dried, chopped root for tea or a simmered decoction - Mixed menopause blends with red clover, sage, soy or St John's wort
Two quality points matter. Some products have been found to contain cheaper Asian Actaea species instead. Choose a product that names Actaea racemosa and states the plant part used.
Blends raise a second problem. If a blend contains St John's wort, the drug interaction risk comes from that herb, not from black cohosh.
Black cohosh has a long written record in North America.
Indigenous peoples of the eastern woodlands used the root for women's complaints, joint pain, sore throat and snakebite. Settlers copied the use and called it black snakeroot or rattle root.
In the 1800s, Eclectic doctors in the United States prescribed it widely under the name macrotys. It was a leading herb in Lydia Pinkham's Vegetable Compound, a famous patent medicine.
German makers standardised the extract from the 1950s onward. Most modern trials used those German products.
Stop taking it and get medical help the same day if you notice: - Yellow skin or yellow eyes (jaundice) - Dark urine or pale stools - Pain under your right ribs - Unusual tiredness, loss of appetite or ongoing nausea - Itching all over with no rash
Book a routine appointment if you get spotting or any vaginal bleeding after menopause. That always needs checking, whatever supplement you take.
Tell your surgeon or anaesthetist before any planned operation. Also tell your doctor if hot flushes are severe, since there are prescription options.
In the United States it is sold as a dietary supplement. The FDA does not check that it works before sale.
In the UK and the EU it is sold under a traditional herbal registration, and labels must carry a liver warning. Australia requires a similar liver warning. It is not a prescription medicine in these countries.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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