What does Black Cohosh do?

Herbal root extract with moderate evidence for reducing hot flashes and menopausal symptoms in women.

Is Black Cohosh safe?

Animal toxicity studies found high-dose black cohosh extract caused megaloblastic anemia-like changes and signs of functional vitamin B12 deficiency in mice — long-term human safety at high doses is not established

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Black Cohosh

Also known as: Actaea racemosa, Cimicifuga racemosa, Remifemin, BNO 1055, Ze 450

Effective Dosage

40 mg/day extract (based on clinical trial data)

What the Science Says

Black cohosh is a North American plant root extract traditionally used to ease menopause symptoms. Clinical trials and a 2026 International Menopause Society systematic review found moderate-certainty evidence that it reduces vasomotor symptoms like hot flashes and night sweats, and one RCT showed it improved objective sleep quality in postmenopausal women. Results are not universal — one Thai RCT found 40 mg/day was no better than placebo — suggesting it may work better in some populations than others.

What It Doesn't Do

Won't replace hormone therapy for severe menopause symptoms. No solid evidence it protects bones — an animal study found it had no effect on bone mineral density. Not proven to boost estrogen levels meaningfully on its own. Don't expect it to work the same for everyone — results vary significantly across studies and populations.

Evidence-Based Benefits

Black cohosh shows moderate-certainty evidence for reducing vasomotor and menopausal symptoms (hot flushes, night sweats, somatic and psychological scores) in postmenopausal women, as supported by a 2026 International Menopause Society systematic review (PMID: 41498229) and multiple RCTs (PMID: 40131516, PMID: 33331798). It also demonstrated significant improvement in objective sleep quality — including increased sleep efficiency and reduced wake-after-sleep-onset — in a 6-month RCT of postmenopausal women with sleep disturbance (PMID: 26000551).

Moderate Evidence

Effective at: 40 mg/day extract studied; combination products vary — no universally established dose from provided studies

Source: auto-research

Absorption & Bioavailability

Unknown — no pharmacokinetic data provided in the reviewed studies. Absorption and metabolism are not well characterized in humans.

Red Flags to Watch For

Animal toxicity studies found high-dose black cohosh extract caused megaloblastic anemia-like changes and signs of functional vitamin B12 deficiency in mice — long-term human safety at high doses is not established
Black cohosh may interact with prescription drugs by affecting cytochrome P450 enzymes (CYP1A2, CYP2D6, CYP3A4) — tell your doctor if you take any medications
Most combination products studied include soy isoflavones and other herbs, making it impossible to isolate black cohosh's individual contribution
Clinical trial reporting quality is inconsistent — a 2025 systematic review found wide variation in adherence to research standards, meaning some positive results may be unreliable
Not recommended for women with hormone-sensitive conditions (e.g., estrogen-receptor-positive breast cancer) without medical supervision

Research Sources

PubMed
NIH DSLD

This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-04-06