Black Cohosh

Black cohosh is said to be useful for menopausal symptoms Symptoms and Signs Menopause is physiologic or iatrogenic cessation of menses (amenorrhea) due to decreased ovarian function. Manifestations may include hot flushes, night sweats, sleep disruption, and genitourinary... read more (eg, hot flushes, mood lability, tachycardia, vaginal dryness), for menstrual symptoms, and for arthralgias in rheumatoid arthritis or osteoarthritis.

Evidence regarding benefit in relieving menopausal symptoms is conflicting (1 References Black cohosh is the underground stem of a plant that can be ingested directly in powdered form or extracted into tablet or liquid form. It should be standardized to contain certain triterpenes... read more ). There are few reliable data on its effectiveness for other disorders and symptoms.

A systematic review included 16 randomized controlled trials of women (n=2027) using oral preparations of black cohosh (average dose 40 mg). There was no significant difference between black cohosh and placebo in the frequency of hot flushes (3 trials; 393 women) or in menopausal symptom scores (4 trials; 357 women) (1 References Black cohosh is the underground stem of a plant that can be ingested directly in powdered form or extracted into tablet or liquid form. It should be standardized to contain certain triterpenes... read more ). A 2016 review of botanical products that included black cohosh also found no benefit for menopausal symptoms (2 References Black cohosh is the underground stem of a plant that can be ingested directly in powdered form or extracted into tablet or liquid form. It should be standardized to contain certain triterpenes... read more ).

A 2017 network meta-analysis in women with an intact uterus found that, compared to placebo, black cohosh decreased vasomotor menopausal symptoms. However, black cohosh was not as effective as hormonal treatments (3 References Black cohosh is the underground stem of a plant that can be ingested directly in powdered form or extracted into tablet or liquid form. It should be standardized to contain certain triterpenes... read more ).

A 2021 review of 35 studies and one meta-analysis (43,759 subjects) of isopropanolic black cohosh extract found benefit compared to placebo for psychological and neurovegetative symptoms (eg, sleep, concentration, fatigue) of menopause. The product was more effective in higher doses or combined with St. John's wort (4 References Black cohosh is the underground stem of a plant that can be ingested directly in powdered form or extracted into tablet or liquid form. It should be standardized to contain certain triterpenes... read more ). A lack of standardization of the supplement product used between studies indicates that more research is necessary to reach definitive conclusions.

Adverse effects are uncommon. The most likely are headache, rash, and gastrointestinal distress. Dizziness, diaphoresis, and hypotension (if high doses are taken) may occur.

Black cohosh is contraindicated in patients with aspirin sensitivity, liver disease, hormone-sensitive cancers (eg, certain kinds of breast cancer per animal data), stroke, or high blood pressure. The US Pharmacopeia (USP), based on a few case reports (5 References Black cohosh is the underground stem of a plant that can be ingested directly in powdered form or extracted into tablet or liquid form. It should be standardized to contain certain triterpenes... read more ), has recommended that black cohosh products be labeled with a warning declaring that they may be hepatotoxic.

Additionally, a woman developed bradycardia due to reversible complete heart block after taking an herbal supplement containing black cohosh (6 References Black cohosh is the underground stem of a plant that can be ingested directly in powdered form or extracted into tablet or liquid form. It should be standardized to contain certain triterpenes... read more ).

There is little clinical evidence that black cohosh interferes with medications. However, a recent in vitro study suggests that black cohosh may inhibit the biotransformation or effectiveness of tamoxifen and irinotecan, both chemotherapy drugs (7 References Black cohosh is the underground stem of a plant that can be ingested directly in powdered form or extracted into tablet or liquid form. It should be standardized to contain certain triterpenes... read more ).

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