Black cohosh as a remedy for hot flushes
Although black cohosh is one of the most extensively studied herbs used for treating menopausal symptoms, its effectiveness is still not fully clear. Some studies suggest that it can help with hot flushes and night sweats, while others show no improvements in these symptoms when using the herbal extract.
More specifically, research indicated that black cohosh extract is similarly effective as other medication like topical hormones in relieving common menopausal symptoms. After reviewing 35 studies in more than 43,000 women, a large analysis concluded that black cohosh has a positive effect on hot flushes and night sweats resulting from natural menopause. This benefit was apparent compared to placebo, although the effectiveness of black cohosh extract was shown to be generally lower than that of hormone therapy. Despite this, the authors of several studies concluded that black cohosh is a safe hormone-free alternative therapy for treating these menopausal symptoms.
Dried black cohosh. (Adobe Stock)
Other studies led to contrary results. For example, a high-quality clinical trial from 2006 did not demonstrate any improvement in hot flushes with black cohosh compared to placebo. Similarly, some larger meta-analyses were not able to show the difference between black cohosh and placebo in lowering the frequency or intensity of these symptoms.
This discrepancy in clinical studies could be the result of variations in the preparations used. Unlike synthetic drugs, herb extracts usually contain several active ingredients, and their composition can vary due to many factors (e.g., cultivation, harvesting, extraction procedures) which may impact the effectiveness. We currently have only limited knowledge of the optimal composition of black cohosh preparations and therapy duration. Further clinical trials with larger participant numbers and longer follow-up periods are needed to gather more conclusive evidence.
Positive effect of black cohosh on depression and anxiety
Black cohosh extract has also been found to have a beneficial effect on depression and anxiety in postmenopausal women. Several randomized controlled studies have shown that the herb can reduce symptoms of anxiety and depression to a similar extent as hormone therapy. One study even reported a greater improvement in depressive symptoms when black cohosh was combined with St John's wort. Another study found that a combination of black cohosh with an antidepressant improved depression more effectively than the antidepressant alone.
Black cohosh is associated with healthier skin
A combination of black cohosh, soy, chasteberry and evening primrose extracts has shown a positive effect on skin health in postmenopausal women. In a 12-week clinical trial, this nutraceutical blend showed significant improvements in skin elasticity, roughness, scaliness and wrinkles compared to the placebo group after 12 weeks. These findings suggest that supplementation with this combination of herbs can support skin health and provide measurable anti-aging effects on skin structure and integrity in menopausal women.
Effect of black cohosh on other menopausal symptoms
Black cohosh has also been studied for its effects on some other menopausal symptoms, such as genitourinary syndrome (discomfort in the intimate area and bladder function) and osteoporosis. One of the largest studies on black cohosh, the Herbal Alternatives for Menopause (HALT) Study, found no significant effects on vaginal dryness and changes in reproductive hormone levels. Of note, this study also reported that black cohosh, alone or as part of a multi-botanical regimen, was not associated with improvements in hot flushes and night sweats.
Although experimental data show that black cohosh extract may have potential benefits for osteoporosis by promoting bone health, the evidence of its effectiveness for treating or preventing osteoporosis is still conflicting. More clinical research is needed.
No increased risk for breast cancer or weight gain
A review of 26 studies found no evidence linking black cohosh to an increased risk of breast cancer.
Black cohosh does not cause weight gain
Weight gain is a common concern during perimenopause and postmenopause and there have been conflicting reports about whether taking black cohosh can increase weight. A recent review found no relationship between black cohosh intake and weight gain. Experimental studies confirmed these results.
Therapy with black cohosh is safe
Overall, no serious harmful effects were observed in people taking black cohosh for as long as 12 months in clinical trials. Black cohosh can cause some mild and temporary side effects, such as stomach upset, headache, rash and a feeling of heaviness.
While there have been reports linking black cohosh to liver problems, the exact connection is still not well established. Importantly, a meta-analysis of five clinical trials involving perimenopausal and postmenopausal women revealed no notable impairment in liver function when used for 3-6 months.
In reports of liver-related side effects associated with black cohosh, it is still uncertain whether these effects were directly caused by black cohosh or by impurities or wrong herbs in certain products. You should therefore check for quality of black cohosh products available on the market to avoid impurities or additives that may lead to potential side effects. Your gynecologist may also advise you on suitable preparations.
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