Black Cohosh
Actaea racemosa / Cimicifuga racemosa
Evidence Rating
Confidence Level
Traditions
Last Updated
Summary
Black Cohosh is the best-studied herbal medicine for menopausal vasomotor symptoms in the European phytotherapy tradition. It holds "well-established use" status from the EMA/HMPC, a positive Commission E monograph, and an ESCOP monograph. The primary commercial product, Remifemin (isopropanolic extract, 40 mg/day), has demonstrated efficacy comparable to low-dose conjugated estrogens in some trials. The mechanism is non-estrogenic, acting through serotonergic, dopaminergic, and GABAergic pathways. The hepatotoxicity debate, which generated significant regulatory concern in the mid-2000s, has been largely resolved: rigorous causality assessments found no probable causal link in the vast majority of reported cases, with product adulteration and confounding factors implicated instead.
Drug Interactions
This herb has significant drug interactions. Do not use if you are taking medications without consulting a healthcare provider first. See detailed interaction information below.
Regulatory Status
| Regulatory Body | Status |
|---|---|
| Commission E (Germany) | âś“ Approved |
| ESCOP (European) | âś“ Approved |
| EMA/HMPC (EU) | âś“ Approved |
Metadata
| Field | Detail |
|---|---|
| Common Names (English) | Black Cohosh, Black Bugbane, Black Snakeroot |
| Common Names (German) | Traubensilberkerze, Wanzenkraut |
| Botanical Name | Actaea racemosa L. (syn. Cimicifuga racemosa (L.) Nutt.) |
| Plant Family | Ranunculaceae |
| Part Used | Rhizome with roots (Cimicifugae rhizoma) |
| Evidence Quality Rating | Strong — Well-established use (EMA/HMPC), Commission E approved, ESCOP monograph, multiple RCTs |
Approved Indications
Commission E (Germany, 1989)
- Premenstrual discomfort
- Dysmenorrhea (painful menstruation)
- Climacteric (menopausal) neurovegetative symptoms
ESCOP (European Scientific Cooperative on Phytotherapy)
- Climacteric symptoms including:
- Hot flushes
- Profuse sweating
- Sleep disorders
- Nervous irritability
EMA/HMPC (European Medicines Agency)
- Status: Well-Established Use (the highest category)
- Indication: Relief of menopausal complaints such as hot flushes and profuse sweating
- Monograph Reference: EMA/HMPC/600717/2007 (Revision 1, 2018)
- Duration: Not to be used for longer than 6 months without medical supervision
- Note: Well-established use means bibliographic evidence of safety and efficacy covering at least 10 years in the EU
Agreement/Disagreement Between Bodies
- Agreement: All three bodies agree on menopausal/climacteric symptoms as the primary indication
- Disagreement: Commission E additionally lists PMS and dysmenorrhea, which are not emphasized by ESCOP or EMA. The EMA monograph is the most conservative, focusing specifically on vasomotor symptoms
Conditions Treated
Primary (Evidence-Supported)
- Menopausal vasomotor symptoms: Hot flashes, night sweats — strongest evidence
- Menopausal neurovegetative symptoms: Sleep disturbances, irritability, mood changes
Secondary (Commission E / Traditional)
- Premenstrual syndrome (PMS)
- Dysmenorrhea
- Neurovegetative complaints in peri-menopause
Investigated but Unconfirmed
- Bone density preservation (BNO 1055 showed improvement in bone markers, but not a primary indication)
- Breast cancer-related hot flashes (some positive observational data, but insufficient for recommendation)
Mechanism of Action
Key Finding: Non-Estrogenic Mechanism
Black Cohosh does NOT act through direct estrogen receptor binding. This is a critical distinction from earlier hypotheses.
Specific Compounds
| Compound Class | Key Compounds | Activity |
|---|---|---|
| Triterpene glycosides (>42 identified) | Actein (~2.3% of extract), 23-epi-26-deoxyactein, cimifugoside | GABAergic activity; structures similar to steroids but no ER binding |
| Phenylpropanoids | Caffeic acid, fukinolic acid, cimicifugic acids | Antioxidant, anti-inflammatory |
| Serotonin analogues | N-omega-methylserotonin | Serotonergic receptor binding |
Proposed Mechanisms (Multiple, Not Mutually Exclusive)
- Serotonergic pathway: Black Cohosh contains serotonin analogues and may modulate serotonin receptors, explaining effects on thermoregulation (hot flashes are mediated in part by serotonin in the hypothalamus)
- Dopaminergic activity: Some dopamine receptor binding has been demonstrated
- GABAergic activity: Actein-like triterpenes show GABA-A receptor activity, potentially explaining anxiolytic and sleep-promoting effects
- Opioid receptor activity: Some evidence for mu-opioid receptor binding [NEEDS-RESEARCH]
- Anti-inflammatory/antioxidant: Phenylpropanoid compounds contribute to overall activity
What It Does NOT Do
- Does not bind estrogen receptors alpha or beta in clinically relevant concentrations
- Does not increase endometrial thickness (BNO 1055 study, n=400, 52 weeks)
- Does not cause vaginal hyperplasia
- Does not alter estradiol, FSH, or LH levels significantly
Clinical Evidence Summary
Key Clinical Trials
Remifemin (Isopropanolic Extract) Trials
| Study | Design | N | Duration | Key Finding |
|---|---|---|---|---|
| Osmers et al. 2005 | RCT, DB, PC | 304 | 12 weeks | Significant reduction in Menopause Rating Scale vs. placebo |
| Nappi et al. 2005 | RCT, active comparator | 64 | 3 months | BNO 1055 equipotent to conjugated estrogens 0.6 mg |
| Wuttke et al. 2003 | RCT, DB, active comparator | 62 | 3 months | BNO 1055 comparable to CE 0.6 mg; improved bone markers |
| Liske et al. 2002 | RCT, DB, dose-finding | 152 | 12 weeks | 40 mg and 127 mg both effective; no dose-response advantage for higher dose |
Breast Cancer Patients (Observational)
- Prospective trials in breast cancer patients/survivors taking Remifemin (20-40 mg/d) show reductions as high as 56% (95% CI: 40%-71%) in hot flash scores
- However, evidence insufficient for formal recommendation in this population
Cochrane Review (Leach & Moore, 2012)
- Reviewed available RCTs; concluded there was insufficient evidence of consistent quality
- Noted methodological heterogeneity across trials
- Did NOT conclude that Black Cohosh was ineffective, but called for more standardized research
Effect Sizes
- Hot flash frequency reduction: Approximately 26-56% in various trials
- Menopause Rating Scale: Significant improvement over placebo (specific effect sizes vary by trial)
- Comparator equivalence: Shown comparable to conjugated estrogens 0.6 mg in some trials, though not consistently
The Hepatotoxicity Debate
Background
Beginning in the early 2000s, case reports of liver injury in Black Cohosh users raised regulatory alarm. Over 50 case reports were ultimately published, including cases of acute liver failure requiring transplant. This led to:
- Australian TGA warning (2006)
- European HMPC safety review
- Required label warnings in multiple countries
Rigorous Causality Assessment — Key Findings
| Assessment | Method | Result |
|---|---|---|
| Teschke et al. 2009 | CIOMS/RUCAM scale (hepatotoxicity-specific) | 68 of 69 cases: excluded, unlikely, unrelated, or unassessable causality |
| Naser et al. 2011 | Systematic analysis of 30 case reports | Insufficient evidence for causal relationship |
| EMA/HMPC Review 2007 | Regulatory causality assessment | Only 4 of 42 patients showed possible/probable causality |
| Diagnostic algorithm analysis | Structured causality methodology | No evidence for causal relationship |
Confounding Factors Identified
- Failure to identify the specific Black Cohosh product used
- Use of herbal mixtures containing multiple ingredients alongside Black Cohosh
- Co-medication with hepatotoxic synthetic drugs or supplements
- Missing temporal association between Black Cohosh use and liver disease onset
- Insufficiently excluded pre-existing liver diseases
- Possible product adulteration (substitution with Asian Actaea species, which contain different compounds)
Current Consensus
- European position: The EMA/HMPC maintained the monograph with label warnings about potential liver effects but upheld the well-established use status
- Product-specific safety: No evidence of hepatotoxicity with the isopropanolic extract (Remifemin) at doses of 40-128 mg in clinical trials
- Adulteration hypothesis: Strong suspicion that some cases involved products adulterated with related but distinct species (Actaea cimicifuga, Actaea dahurica) that are hepatotoxic
- Practical recommendation: Patients should be counseled to discontinue use and consult a physician if signs of liver injury appear (jaundice, dark urine, upper abdominal pain)
European vs. US/Anglophone Consensus
| Aspect | European Consensus | US/Anglophone Consensus |
|---|---|---|
| Regulatory status | Well-established use (EMA); approved herb (Commission E) | Dietary supplement only (FDA does not evaluate efficacy) |
| Clinical utility | Accepted first-line herbal option for menopausal symptoms | Cautiously recommended; NCCIH notes evidence is mixed |
| Hepatotoxicity | Largely resolved; label warning but continued approval | Greater residual concern; stronger warnings emphasized |
| Mechanism | Non-estrogenic consensus well-established | Non-estrogenic generally accepted but less widely communicated |
| Product standardization | Specific extracts (Remifemin, BNO 1055) with documented efficacy | Generic “black cohosh” products of varying quality |
| Breast cancer context | Cautious but not contraindicated per se | MSKCC and others note insufficient evidence for safety in BC patients |
Safety Profile
Contraindications
- Known hypersensitivity to Black Cohosh or Ranunculaceae
- Hepatic impairment or history of liver disease (precautionary)
- Not recommended for use beyond 6 months without medical supervision
- Not recommended for children or adolescents under 18
Drug Interactions
- CYP3A4 inhibition: In vitro data shows competitive inhibition by triterpene glycosides (IC50: 2.3-5.1 microM for individual compounds; IC50 16.5 microg/mL for extract)
- CYP2D6 inhibition: In vitro IC50 of 50.1 microg/mL for extract
- Tamoxifen: Potential to inhibit metabolic activation of tamoxifen to active metabolites (66-80% inhibition in vitro); clinical significance UNKNOWN but warrants caution
- Hepatotoxic medications: Theoretical additive risk with other hepatotoxic drugs
- Statins: No formal interaction data but monitor in combination with hepatotoxic statins [UNCERTAIN]
Side Effects
- Gastrointestinal complaints (rare)
- Headache (rare)
- Dizziness (rare)
- Allergic skin reactions (very rare)
- Weight gain (reported but not confirmed in controlled studies)
Pregnancy and Lactation
- Contraindicated in pregnancy: No safety data; potential uterotonic effects
- Contraindicated in lactation: Insufficient data
- Hormone-sensitive conditions: Despite non-estrogenic mechanism, precautionary avoidance often recommended in estrogen-receptor-positive breast cancer, though this is debated
Clinical Dosage
Recommended Forms and Doses
| Form | Preparation | Daily Dose | Notes |
|---|---|---|---|
| Isopropanolic extract (Remifemin) | Standardized extract equivalent to 40 mg root/rhizome | 20-40 mg extract/day (1-2 tablets) | Best-studied form; 20 mg once daily or 20 mg twice daily |
| Ethanolic extract (BNO 1055) | 40% ethanol extract | 40 mg/day | Used in several clinical trials; shown equipotent to CE 0.6 mg |
| Dried root/rhizome | Various preparations | 40-200 mg/day | Less standardized; not preferred |
| Tincture (1:10, 60% ethanol) | Liquid extract | 0.4-2 mL/day | Traditional form |
Key Products
| Product | Manufacturer | Extract Type | Standardization |
|---|---|---|---|
| Remifemin | Schaper & Brummer (Germany) | Isopropanolic | Equivalent to 20 mg root/rhizome per tablet |
| Remifemin Plus | Schaper & Brummer | Isopropanolic + St. John’s Wort | Combination product |
| Klimadynon/BNO 1055 | Bionorica (Germany) | Ethanolic (40%) | 2.5 mg native extract per tablet |
Duration
- EMA recommends maximum 6 months without medical supervision
- Clinical trials have documented safety up to 12 months (BNO 1055 endometrial study)
- Onset of effect typically 4-8 weeks
Connections
- Compare with Red Clover and Soy Isoflavones — these are estrogenic alternatives, while Black Cohosh is non-estrogenic
- The CYP interaction with tamoxifen is clinically relevant for breast cancer survivors using any of these herbs
Related Herbs
Red Clover
Trifolium pratense
Red Clover is a significant source of isoflavones (formononetin, biochanin A, genistein, daidzein) used primarily for menopausal hot flashes. Unlike soy isoflavones, Red Clover contains higher proportions of the methylated isoflavones formononetin and biochanin A. Meta-analyses show a statistically significant reduction in hot flash frequency (-1.73/day vs. placebo), with best results at doses of 80+ mg isoflavones/day for 12+ weeks. However, formal European regulatory recognition is limited -- there is no Commission E or ESCOP monograph specifically for menopausal use, and the EMA assessment is not as developed as for Black Cohosh or Vitex. Promensil is the most studied commercial product. Safety appears acceptable for up to 2 years, but uncertainty persists regarding use in hormone-sensitive cancers.
Sage
*Salvia officinalis*
Sage is a well-established European medicinal herb approved by Commission E, ESCOP, and EMA for excessive perspiration (especially menopausal hot flashes and night sweats), inflammation of the mouth and throat, and mild dyspeptic complaints. The leaf contains thujone-bearing essential oil alongside rosmarinic acid and other phenolic compounds. Clinical evidence for its anti-hydrotic (sweat-reducing) effect is moderate, supported by several open-label and a few controlled trials showing 50-64% reductions in hot flash intensity. Thujone content requires attention to dosage limits and duration; the EMA recommends limiting use of thujone-containing preparations to 2-4 weeks unless under medical supervision. Sage occupies a unique niche in phytotherapy as one of the few herbal medicines with a specific indication for hyperhidrosis.
Soy Isoflavones
Glycine max
Soy Isoflavones are the most extensively studied phytoestrogens for menopausal symptoms, with dozens of RCTs and multiple meta-analyses. A 2025 meta-analysis (12 RCTs, n=533) confirms a statistically significant but modest effect on menopausal symptoms (Hedges' g = -0.25). However, a landmark 2024 meta-analysis demonstrated that soy isoflavones have NO effect on four key estrogenicity markers (endometrial thickness, vaginal maturation index, FSH, estradiol), fundamentally challenging the "phytoestrogen" classification. The breast cancer question has shifted from concern to cautious reassurance -- epidemiological data shows reduced risk with dietary soy intake, and post-diagnosis consumption is associated with 25% reduced recurrence. Thyroid effects are minimal (modest TSH elevation, no clinical significance in euthyroid individuals). The equol producer status (approximately 30% of Western populations) may be a key determinant of individual response.