Black Cohosh for Menopause: Extracts, Benefits and Liver Safety

What is black cohosh?

Black cohosh is Actaea racemosa, a North American plant whose root and underground stem are used in menopause preparations. The older name Cimicifuga racemosa also appears on labels. Products include named extracts, generic extracts and root powder.

Blue cohosh is a different plant. Its name does not make it a substitute for black cohosh, and the research below does not apply to it.

Women usually consider black cohosh supplements for hot flashes and night sweats. The amount only becomes meaningful once you know the preparation: milligrams of actual extract, dried-root equivalent and a standardized chemical marker are different quantities.

How was black cohosh used historically?

Black cohosh’s medicinal history is broader than menopause. NCCIH^[1] describes Native American uses for menstrual cramps, kidney ailments, sore throat and malaria. A USDA historical bibliography^[2] also records rheumatic complaints and childbirth-related uses, followed by adoption by European settlers and American physicians. These institutional accounts do not identify one shared recipe or practice across Indigenous communities.

The preparations become clearer in a surviving physician’s account. In his 1869 Physiomedical Dispensatory, William Cook^[3] described root powder, water infusions and alcohol tinctures taken internally for rheumatic pain, painful menstruation and respiratory complaints. He also discussed childbirth uses.

Modern research mainly tests manufactured root/rhizome extracts.

Why do women take black cohosh?

When to ask a doctor before taking it

Discuss the choice if you have liver disease, unexplained vaginal bleeding, a history of hormone-sensitive cancer or use tamoxifen or hormone treatment.

Understanding black cohosh labels

Look for Actaea racemosa, root/rhizome (rhizome means underground stem) and extraction details. Check whether the stated milligrams describe actual extract or an equivalent weight of starting root. Native extract means the actual extract before that conversion; a small amount can represent a much larger root weight.

There is no common amount that works across all preparations or an established dose that guarantees relief or makes indefinite use safe.

Some labels state a percentage or milligrams of triterpene glycosides, a group of compounds used as a chemical marker. That number helps describe the extract, but the active ingredient responsible for any symptom relief has not been established. The isopropanol extract studied in several trials is described by its root equivalent and is not standardized to that marker. A higher marker percentage has not been shown to produce better symptom relief.

When black cohosh is part of a combination product

An example creatine blend for women^[4] combines black cohosh with creatine, ashwagandha, DIM and L-theanine. Its retail Supplement Facts panel^[5] lists 20 mg organic black cohosh powder alongside 5 g creatine monohydrate per serving. The black-cohosh amount is neither 20 mg of a characterized extract nor evidence that the blend relieves hot flashes. Read each ingredient and amount separately; the creatine research does not validate the added menopause ingredients.

Drawbacks and side effects

Product identity complicates the liver reports. NIH's review^[6] notes that impurities or another Actaea species might explain some cases, but the implicated products were not independently tested to establish that explanation. Nor do the reports prove black cohosh caused each injury. The practical warning still applies: stop the product and seek care if signs of liver trouble appear.

Why do recommendations disagree?

A favorable extract trial

A 12-week Ze 450 trial^[7] randomized 180 women with menopausal complaints to placebo or 6.5 or 13 mg of dry extract daily. Ze 450 is made with 60% ethanol; these amounts describe the extract itself, not the weight of starting root.

Among the 166 women included in the efficacy analysis, both doses improved the Kupperman Menopausal Index more than placebo. This scale combines symptoms rather than simply counting daily hot flashes. At least a 50% reduction in the score occurred in about 40% at 6.5 mg, 69% at 13 mg and 7% with placebo. The higher dose also performed better than the lower dose in the trial’s planned comparison.

The manufacturer funded the study and employed three authors. The trial lasted twelve weeks. For women who left at the interim visit, the analysis used their last available results in place of later measurements. It provides a positive result for Ze 450, without establishing how it compares with other extracts or whether its benefit persists with longer use.

Trials that did not confirm a hot-flash benefit

In Newton’s year-long HALT trial^[8], 351 women entered five treatment groups. Black cohosh alone at 160 mg a day of a 70% ethanolic extract, and the herbal combinations, did not clearly outperform placebo; hormone therapy did.

Geller’s separate year-long trial^[9] compared 128 mg/day of an ethanolic black-cohosh extract with placebo, red clover and hormone therapy in women having frequent hot flashes and night sweats. Eighty-nine women were randomized and 80 completed the study. Symptoms declined in the black-cohosh and placebo groups, but black cohosh did not provide a significant advantage. Symptom intensity was actually higher with black cohosh at six and nine months. These results help explain why improvement while taking a supplement is not enough, by itself, to establish that the supplement caused it.

Symptoms during and after breast cancer treatment

Cancer treatment can bring on or worsen menopause symptoms. Black cohosh has been investigated for these symptoms, including in women taking tamoxifen, but the studies give conflicting answers.

In an uncontrolled six-month study^[10], 50 women taking tamoxifen received an isopropanolic black-cohosh extract. The study reports one to four 2.5 mg tablets daily. Their average combined symptom score fell from 17.6 to 13.6; hot flashes, sweating, sleep problems and anxiety improved, while urinary/genital and musculoskeletal complaints did not. With no comparison group, the study cannot separate an extract effect from changes over time, expectations or other care.

The placebo-controlled Jacobson trial^[11] followed 85 breast cancer survivors, including 59 taking tamoxifen, for about two months. Both groups reported fewer and less intense hot flashes, with no significant difference between black cohosh and placebo. Sixty-nine women completed all three symptom diaries. The preparation was poorly characterized in the later NCI assessment, which limits comparison with a named modern extract.

Another crossover study^[12] randomized 132 women with hot flashes to black cohosh, 20 mg twice daily, or placebo for four weeks, then switched treatments. Hot-flash scores fell by 20% with black cohosh and 27% with placebo; frequency fell by 17% and 26%, respectively. Neither difference was statistically significant.

A different trial in 85 women beginning ovarian-suppressing treatment^[13] found lower combined menopause symptom scores when Remifemin was added to ovarian-suppressing treatment for twelve weeks. Its comparison was standard treatment alone, without a placebo. Hormone levels were similar between groups, while cervical cysts were more frequent in the Remifemin group. That combination of findings needs to be weighed separately from the blinded hot-flash trials.

For someone taking tamoxifen or ovarian-suppressing treatment, the choice belongs in a discussion with the oncology team, including the exact product and the symptoms being treated.

Sleep after menopause

A six-month randomized trial^[14] enrolled 48 early postmenopausal women aged 45–60 who had sleep complaints; 42 completed it. Compared with placebo, black cohosh improved sleep efficiency^[15]—the percentage of time in bed spent asleep—and reduced time spent awake after initially falling asleep. Both were measured by overnight sleep monitoring. Improvement on the women’s own sleep-quality questionnaire was less clear.

That is a promising objective signal from a small study, rather than an established sleep treatment. The size of the benefit over placebo and the exact preparation have not been verified from the full report, so it does not yet support choosing a particular extract or dose for insomnia.

Does it replace estrogen or protect bone?

The idea that black cohosh simply supplies plant estrogen is too broad. NCI distinguishes the hydroalcoholic extracts used clinically from other laboratory extracts^[16]; estrogen-like actions cannot be assumed across them. Effects on brain signalling, including serotonin pathways, have been proposed, but the mechanism responsible for symptom relief is not settled.

In the year-long Geller trial, the 128 mg extract did not significantly improve bone density or levels of estradiol, a form of estrogen^[17], relative to placebo. Other black-cohosh studies have examined bone-turnover markers^[16], which reflect bone formation or breakdown. Those measurements differ from the amount of bone preserved.

Why the guidance differs

The European Medicines Agency^[18] recognizes specified solvent extracts for menopausal complaints. Its conclusion does not cover combination products or every retail powder. The 2023 North American menopause statement^[19] does not recommend supplements and herbal remedies for hot flashes.

The studies behind these discussions differ in extract, patient group and what they measure. A combined symptom score, a count of hot flashes and a sleep measurement answer different questions. Reviews also differ in whether they include black cohosh alone or mixtures with other herbs.

The bottom line

Some specified black-cohosh extracts have positive menopause symptom trials, including the twelve-week Ze 450 study. Other well-controlled studies found no hot-flash advantage. Results during breast cancer treatment and for sleep add useful questions, but they do not yet establish a dependable treatment or a universal dose.

Follow the product directions and seek advice suited to your health and treatments. Reassess whether symptoms actually improve, and take the liver warning seriously. If hot flashes disrupt sleep or daily life, discuss the available treatment options; if you are receiving cancer treatment, include the oncology team before adding black cohosh.

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