Black Cohosh for Menopausal Symptoms
Current evidence shows that black cohosh has insufficient proven benefit for treating menopausal symptoms, with the highest quality systematic review finding no significant difference compared to placebo for hot flashes or overall menopausal symptom scores. 1, 2
Evidence Summary
Efficacy Data
A 2012 Cochrane systematic review of 16 randomized controlled trials (2027 women) found no significant difference between black cohosh and placebo for hot flush frequency (mean difference 0.07 flushes per day; 95% CI -0.43 to 0.56; P=0.79) or menopausal symptom scores (SMD -0.10; 95% CI -0.32 to 0.11; P=0.34). 2
Limited data show possible benefit for vasomotor symptoms in the general population, but randomized trials specifically in breast cancer survivors show no benefit. 1
A review of clinical data suggests black cohosh may be useful for hot flashes, profuse sweating, insomnia, and anxiety, but the overall quality of published clinical trials is low. 3
The most recent evidence indicates black cohosh is not effective for treating menopausal symptoms in breast cancer survivors being treated with tamoxifen. 3
Comparison to Proven Therapies
Hormone therapy significantly outperforms black cohosh, reducing daily hot flush frequency and menopausal symptom scores (SMD 0.32; 95% CI 0.13 to 0.51; P=0.0009) in five trials. 2
Pharmacological options (SSRIs, SNRIs, gabapentin, clonidine) generally show greater efficacy than natural supplements including black cohosh for managing vasomotor symptoms. 1
Safety Profile
Evidence on the safety of black cohosh is inconclusive due to poor reporting in clinical trials. 2
Adverse reactions observed include nausea, vomiting, headaches, dizziness, mastalgia, and weight gain. 3
At least 4-12 weeks of treatment may be required before any therapeutic benefits become apparent. 3
The estrogenic effects of black cohosh are controversial, with more recent data indicating potential anti-estrogenic activity. 3
Black cohosh should not be administered to children or during pregnancy and lactation due to potential effects on sex hormones. 3
Clinical Recommendation
Given the lack of proven efficacy compared to placebo and the availability of evidence-based alternatives, black cohosh should not be recommended as first-line therapy for menopausal symptoms. 1, 2
Preferred Treatment Algorithm
First-line: Nonpharmacologic interventions including weight loss ≥10% of body weight, smoking cessation, limiting alcohol intake, acupuncture, cognitive behavioral therapy, and yoga. 4, 1
Second-line: Nonhormonal pharmacologic options such as gabapentin 900 mg/day (reduces hot flash severity by 46% vs 15% with placebo), venlafaxine 37.5-75 mg daily (reduces hot flash scores by 37-61%), or paroxetine 7.5 mg daily (avoid with tamoxifen). 4
Third-line: Menopausal hormone therapy only when nonhormonal options fail, using the lowest effective dose for the shortest duration possible. 4
Important Caveats
If patients specifically request "natural" treatment, high-dose vitamin E (800 IU/day) has limited efficacy but is reasonable for mild symptoms, though doses >400 IU/day are linked to increased all-cause mortality and should be avoided. 4, 1
The uncertain quality and heterogeneity of black cohosh trials, combined with variable dosing (median 40 mg daily) and assessment methods, make it impossible to provide reliable guidance on its use. 2
No drug interactions are reported in the medical literature for black cohosh, but this may reflect inadequate reporting rather than true absence of interactions. 3, 2