Black cohosh has a number of potential benefits — most of them related to women’s health or hormonal balance. Yet, with the exception of menopause symptoms, there is little evidence to support its use for any of these conditions.
Menopause and menopause symptoms
Alleviating menopause symptoms is the reason most people use black cohosh, and it’s one of the uses that has the most compelling evidence to support it.
In one study in 80 menopausal women who were experiencing hot flashes, those who supplemented with 20 mg of black cohosh daily for 8 weeks reported significantly fewer and less severe hot flashes than before they started the supplement (4).
What’s more, other human studies have confirmed similar findings. Though larger studies are needed, black cohosh appears to be beneficial for alleviating menopause symptoms (5).
Although you may see many claims online that black cohosh can improve fertility or help you get pregnant, there’s not a great deal of evidence to support this.
However, research indicates that black cohosh may improve the effectiveness of the fertility drug Clomid (clomiphene citrate) in people who are infertile, increasing their chances of becoming pregnant (6, 7, 8).
Still, these studies were small, and more research is needed to confirm this effect.
Black cohosh is also used for a number of other purposes related to women’s health. However, the evidence supporting these benefits is not as strong as the evidence supporting its benefits for menopause and fertility.
Here are a few more reasons women may use black cohosh to support hormonal balance:
- Polycystic ovarian syndrome (PCOS). Supplementing with black cohosh may increase a woman with PCOS’s chances of getting pregnant on Clomid. Supplementing with black cohosh may also help regulate your cycles if you have PCOS (8, 9).
- Fibroids. One 3-month study in 244 postmenopausal women found that supplementing daily with 40 mg of black cohosh may decrease the size of uterine fibroids by up to 30% (10).
- Premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD). Though there are some claims online that black cohosh can help with PMS or PMDD, there’s no substantial evidence to support this.
- Menstrual cycle regulation. In women with or without PCOS who are receiving fertility treatments like Clomid, black cohosh may help regulate their menstrual cycle (6, 7, 8).
Black cohosh has some potentially estrogenic activity, meaning it behaves like the hormone estrogen, which may worsen breast cancer or increase your breast cancer risk (11).
However, most studies show that black cohosh does not affect your breast cancer risk. In two human studies, taking black cohosh was associated with a decreased risk of breast cancer (11).
In test-tube studies, black cohosh extract exhibited anti-estrogen activity and helped slow the spread of breast cancer cells (12).
Still, more research needs to be done to understand the link between breast cancer and black cohosh.
Black cohosh may have some beneficial effects on mental health, particularly in menopausal women.
One review of studies investigated the use of herbal supplements for anxiety and depression in menopausal women. Researchers found that supplementing with black cohosh had no effect on anxiety, but it was linked to significant improvements in psychological symptoms (13).
Yet, more research is needed before the effect of black cohosh on mental health is fully understood.
Although there’s little evidence that black cohosh can improve sleep, it may help reduce symptoms that are causing sleep disturbances in menopausal women, such as hot flashes.
However, one small study in 42 menopausal women found that supplementing with black cohosh seemed to improve sleep duration and quality (14).
Another study noted that a combination of black cohosh and other compounds — including chasteberry, zinc, ginger, and hyaluronic acid — helped improve hot flashes that were associated with insomnia and anxiety (15).
Still, it’s hard to say whether black cohosh or one of the other ingredients was the beneficial compound in this mixture.
Menopausal women may be at an increased risk of unwanted weight gain, as their estrogen levels naturally decrease (16).
Theoretically, because black cohosh may exhibit estrogenic effects, it may have a small beneficial effect on weight management in menopausal women (16).
However, the evidence to support this is minimal. More and larger human studies are needed to understand the link, if any, between black cohosh and weight management.