Black cohosh: benefits, uses and background

What is black cohosh?

Black cohosh (Actaea racemosa) is a herbaceous perennial plant native to north America that also goes by the rather offputting sounding names of black snakeroot and bugbane, as well as the more appealing name fairy candle, after the tall white racemes that bloom in late spring. Indigenous Americans have long made use of black cohosh's roots and rhizomes, but these days it is most commonly available in tablet form, and can also be sold as a tincture.

What is black cohosh used for?

Black cohosh is used mainly to treat menopause symptoms, but also pre-menstrual symptoms, and has also been promoted for migraine relief, breast cancer and arthritis.

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What’s the history of black cohosh?

Black cohosh has been used by Indigenous Americans as a medicinal plant to treat a variety of gynaecological problems – the roots and rhizomes (shoots from the root) are used. It was used for treating snakebite, lung inflammation and pain during labour and/or childbirth.

What’s the best way to take black cohosh?

Black cohosh supplements are available to buy over the counter in healthfood stores and chemists. It usually comes in the form of a 20mg pill, which is to be taken twice a day. You may also see it in the form of a tincture or extract. Taking it in these forms isn’t so easy to regulate, so if you are unsure it’s best to stick to a supplement with a set dosage.

How much black cohosh should you take?

Recommendations as to how much black cohosh to take vary widely, but the British Herbal Compendium suggests between 40 and 200mg of the dried form of black cohosh, taken in smaller amounts throughout a day, is best.

Does black cohosh really work?

It’s thought that the phytochemicals in black cohosh may have an effect on hormones, although research hasn’t been able to show this effect.

According to a report published in medical journal Menopause^[1], there isn’t evidence of any significant benefits to women going through menopause with related symptoms. There is, however, plenty of anecdotal evidence. This might mean that it has a placebo effect – the psychological effects of believing the medication will work leads to benefits in itself.

There is insufficient evidence to suggest that taking black cohosh supplements for breast cancer, migraines or arthritis offers any significant benefits.

How long does black cohosh take to work?

Women who claim taking black cohosh works usually report improvements within a few weeks of taking the substance. As so little is known about its effects long-term, it is not recommended to take it for more than one year.

Where can I get black cohosh?

Black cohosh supplements are available in health food shops, chemists and online. Aim to take between 20-80mg per day.

What are the side effects of black cohosh?

High doses of black cohosh may cause digestive problems, dizziness, nausea and increased sweating. It has also been linked to liver problems. As there are no guidelines on how much or what kind of black cohosh is contained in supplements, it’s difficult to know whether what you are taking is safe. There have been reports of liver problems while taking black cohosh supplements. If you feel abdominal pain, have unusually dark urine or yellowing of the skin, seek medical help immediately.

Are there any contraindications I should be aware of?

As black cohosh may have an impact on hormones, it should be avoided if you have any hormonal disorders or are taking any hormone-related medications such as Tamoxifen.

If you have any doubts, see your GP to ask whether taking black cohosh supplements are safe for you.

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^[1] https://www.menopause.org/docs/default-source/professional/2015-nonhormonal-therapy-position-statement.pdf