Herb
    Moderate Evidence

    Black Cohosh

    Actaea racemosa / Cimicifuga racemosa

    TL;DR

    Black cohosh is a root extract used at 20–40 mg twice daily for hot flushes. Evidence is mixed but favourable; rare liver injury reports warrant monitoring.

    Ideal For

    • Women with hot flushes and night sweats who cannot or prefer not to use hormone therapy
    • Breast cancer survivors on tamoxifen, with oncology awareness
    • Women with perimenopausal mood and sleep disruption

    Avoid If

    • You have liver disease or raised liver enzymes
    • You are pregnant or breastfeeding
    • You take hepatotoxic medications
    • You have unexplained abdominal pain, dark urine or jaundice

    Frequently Asked Questions

    Overview

    Black cohosh (Actaea racemosa) is a North American woodland plant used traditionally by Indigenous peoples and now among the most widely used botanicals for menopausal symptoms in Europe, where the standardised extracts iCR and BNO 1055 have been studied most.

    Its mechanism is not oestrogenic, despite decades of assumption. Modern work indicates serotonergic activity at 5-HT7 receptors and possible dopaminergic effects, which fits the thermoregulatory nature of hot flushes better than an oestrogen model does. That matters clinically, because it means black cohosh does not stimulate breast or endometrial tissue in the way phytoestrogens might, and it has been studied in breast cancer survivors on tamoxifen.

    Efficacy evidence is genuinely mixed. A Cochrane review found insufficient evidence overall, while several individual trials and later meta-analyses of standardised extracts report meaningful reductions in hot flush frequency and Kupperman index scores versus placebo. The pragmatic reading is that it helps some women modestly and is worth a 12-week trial. Rare cases of hepatotoxicity have been reported; causality is often unclear, but liver function should be checked if symptoms appear.

    How It Works

    • Acts on 5-HT7 serotonin receptors involved in central thermoregulation
    • Possible dopaminergic activity affecting hypothalamic temperature set point
    • Not oestrogen receptor binding — modern assays find no significant oestrogenic activity
    • Triterpene glycosides including actein are considered the active constituents
    • May modulate hypothalamic-pituitary signalling without changing FSH or LH

    Quick Facts

    • Reduces hot flashes
    • Alleviates night sweats
    • Improves sleep in menopause
    • Mood support during menopause
    • Non-estrogenic mechanism

    Benefits & Outcomes

    Hot Flash Reduction

    Womens Health
    Mixed evidence
    Moderate Evidence

    Black cohosh is the most-studied herbal for hot flashes, with meta-analyses showing modest benefit over placebo in perimenopausal women.

    Night Sweats Reduction

    Sleep
    Mixed evidence
    Moderate Evidence
    Effectiveness 3/5

    Modest benefit for menopausal sweats; trial results conflict.

    Menopause Symptom Relief

    Womens Health
    Strong Evidence

    Black cohosh has the strongest botanical evidence for vasomotor menopause symptoms, with meta-analyses showing significant hot flash reduction over placebo.

    Improved Sleep Quality

    Sleep
    Insufficient evidence
    Moderate Evidence

    Sleep improvements appear secondary to fewer night-time hot flushes rather than a direct hypnotic effect.

    Mood Stabilization

    Mood
    Insufficient evidence
    Moderate Evidence

    Mood effects are inconsistent and confounded by symptom relief in menopausal cohorts.

    Hormonal Balance

    Hormonal
    Mixed evidence
    Moderate Evidence

    Black cohosh affects menopausal symptoms without measurably changing hormone levels.

    Health Concerns Addressed

    Night Sweats

    symptom
    Mixed evidence
    Effectiveness 2/5

    Mixed trial evidence for menopausal night sweats only; irrelevant to other causes, which must be ruled out first.

    Menopause

    condition
    Mixed evidence
    Strong Evidence
    Effectiveness 3/5

    Black cohosh may modestly reduce hot flushes, but trial results conflict and liver safety signals require attention.

    Supporting Research
    10 studies

    In vivo effects of goldenseal, kava kava, black cohosh, and valerian on human cytochrome P450 1A2, 2D6, 2E1, and 3A4 phenotypes

    Score: 8/10
    2005
    rct
    n=12

    Gurley BJ, Gardner SF, Hubbard MA +4 more

    Goldenseal produced strong inhibition of both CYP2D6 (approximately 40%) and CYP3A4/5 (approximately 40%); the other botanicals had minimal effect.

    View source

    Safety and Efficacy of Black Cohosh and Red Clover for the Management of Vasomotor Symptoms: A Randomized Controlled Trial

    Score: 8/10
    2009
    rct
    n=89

    Geller SE, Shulman LP, van Breemen RB +10 more

    Neither red clover nor black cohosh reduced vasomotor symptoms significantly more than placebo over 12 months, while hormone therapy did.

    View source

    Black cohosh (Cimicifuga spp.) for menopausal symptoms

    Score: 9/10
    2012
    meta_analysis
    n=2027

    Leach MJ, Moore V

    There was no significant difference between black cohosh and placebo in the frequency of hot flushes or in menopausal symptom scores across the pooled trials.

    View source

    Effects of herbal preparations on symptom clusters during the menopausal transition

    Score: 6/10
    2015
    systematic_review

    Ismail R, et al.

    Black cohosh mixed with other herbals, Rheum rhaponticum, and French maritime pine bark had significant effects on hot flushes and at least one other symptom.

    View source

    Black cohosh extracts in women with menopausal symptoms: an updated pairwise meta-analysis

    Score: 7/10
    2023
    meta_analysis
    n=2310

    Sadahiro R, Matsuoka LN, Zeng BS +1 more

    Black cohosh extracts were associated with significant improvements in overall menopausal symptoms (Hedges' g = 0.575, 95% CI = 0.283 to 0.867, P < 0.001), as well as in hot flashes (Hedges' g = 0.315, 95% CIs = 0.107 to 0.524, P = 0.003)

    View source

    Black cohosh (Cimicifuga racemosa) for menopausal symptoms

    Score: 8/10
    2012
    systematic_review
    n=1164

    Leach MJ, Moore V

    There was insufficient evidence that black cohosh reduced hot flushes or night sweats compared with placebo

    View source

    Assessing the clinical significance of botanical supplementation on human cytochrome P450 3A activity: comparison of a milk thistle and black cohosh product to rifampin and clarithromycin

    Score: 8/10
    2006
    rct

    Gurley B, Hubbard MA, Williams DK +1 more

    Milk thistle and black cohosh appear to have no clinically relevant effect on CYP3A activity in vivo.

    View source

    Treatment of vasomotor symptoms of menopause with black cohosh, multibotanicals, soy, hormone therapy, or placebo: a randomized trial

    Score: 9/10
    2006
    rct
    n=351

    Newton KM, Reed SD, LaCroix AZ +3 more

    Black cohosh, multibotanical preparations and soy did not reduce vasomotor symptom frequency or intensity more than placebo at any timepoint, whereas hormone therapy did.

    View source

    Efficacy of black cohosh extracts for improving low estrogen status induced by postoperative GnRHa treatment in patients with endometriosis: a systematic review

    Score: 6/10
    2020
    systematic_review
    n=745

    Peng J, Xu W, Li X +1 more

    The addition of BCE did not alter hormone levels of patients, including serum estradiol levels [MD=1.24, 95% CI(-4.58, 7.08), P>0.05] and luteinizing hormone levels.

    View source

    Suspected black cohosh hepatotoxicity: no evidence by meta-analysis of randomized controlled clinical trials for isopropanolic black cohosh extract

    Score: 6/10
    2011
    meta_analysis
    n=1117

    Naser B, Schnitker J, Minkin MJ +3 more

    Pooled liver function data from randomized trials of isopropanolic black cohosh extract showed no signal of hepatotoxicity compared with placebo.

    View source

    Safety Information

    Potential Side Effects

    Usually mild: stomach upset, headache, rash and occasional weight gain. The important rare risk is idiosyncratic liver injury, reported in case series across Europe and the US, which prompted labelling warnings in several countries.

    Contraindications

    Do not use with existing liver disease. Discontinue immediately and seek medical review if jaundice, dark urine, upper abdominal pain or unusual fatigue develops. Not for use in pregnancy — it has been used traditionally to induce labour.

    Drug Interactions

    • Hepatotoxic drugs including methotrexate and high-dose paracetamol — additive liver risk
    • Tamoxifen — studied together with no evidence of interference, but discuss with oncology
    • CYP2D6 substrates — weak inhibition reported in vitro
    • Sedatives — possible additive drowsiness

    Pregnancy & Breastfeeding

    Pregnancy: unsafe

    Breastfeeding: insufficient_data

    Dosage Guidelines

    Dosage Used in Studies

    20-40 mg

    Best Time to Take

    Morning and evening, split doses

    Best Form

    A standardised extract such as iCR or BNO 1055 from a supplier that verifies species identity

    Bioavailability

    Used for menopausal symptoms. Mechanism unclear - does not appear to be estrogenic. Rare cases of liver toxicity reported. Discontinue if liver symptoms develop. Effects may take 4-8 weeks.

    Forms Compared

    iCR (Remifemin) standardised extract

    BNO 1055 extract

    Crude root powder

    Food & Timing

    With food to reduce stomach upset

    Medical Disclaimer

    The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.

    Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.