Black Cohosh for Hot Flashes: What the Menopause Research Really Shows

Hot flashes and night sweats are the most common symptoms of menopause, and for many women they last for years, not months. It is no surprise that the supplement aisle is full of “menopause support” formulas, and that black cohosh sits at the center of most of them. It is one of the best-selling herbs in the country for women over forty.

So we went to the strongest research we could find: large reviews, long placebo-controlled trials, and the latest guidance from The Menopause Society, the professional group that sets treatment standards for menopause care in North America. Short version: black cohosh has not beaten placebo convincingly in the best trials. A few other options have a better case. And several treatments that are not supplements at all work well and are worth knowing about.

Why hot flashes happen

A hot flash is a sudden wave of heat, usually across the face, neck and chest, often followed by sweating and chills. Falling estrogen levels around menopause disturb the brain’s temperature control center in the hypothalamus, so it reacts to tiny changes in body temperature as if you were overheating. Researchers now know that a group of brain cells called KNDy neurons plays a central role, which is how a newer class of prescription drugs was developed.

Hot flashes also have a very large placebo response. In many trials, women taking a dummy pill report 20 to 30 percent fewer hot flashes. That is why only placebo-controlled studies tell you anything useful about a remedy.

🌿 Black cohosh: what the best evidence shows

Black cohosh (Actaea racemosa, formerly Cimicifuga racemosa) is a North American plant whose root was used by Native American healers for women’s complaints. It is not a plant estrogen, despite how it is sometimes marketed. How it might work is still unclear.

In 2012, the Cochrane Collaboration, which produces some of the most rigorous reviews in medicine, analyzed 16 randomized trials involving 2,027 women. The reviewers found no significant difference between black cohosh and placebo in the frequency of hot flashes, and concluded there was not enough evidence to support its use for menopausal symptoms.

One of the longest trials, the HALT study published in the Annals of Internal Medicine in 2006, followed women for a full year. Black cohosh alone, a multi-herb formula and the formula plus soy all performed about the same as placebo. Hormone therapy, included as a comparison, clearly worked.

The Menopause Society’s 2023 position statement on non-hormone therapy reviewed all of this and does not recommend black cohosh or other herbal supplements for hot flashes, because the evidence is inconsistent and generally negative.

Our read: some women do say black cohosh helps them, and part of that may be the strong placebo effect. But if you are paying for a menopause formula built around black cohosh, the research says you should not expect much.

🩺 The liver question

There is also a safety issue. Dozens of cases of liver injury have been reported in people taking black cohosh, a few of them serious. It is not proven that black cohosh caused every case, and some products may have been contaminated or misidentified. Still, the U.S. Pharmacopeia recommends that black cohosh products carry a cautionary label about liver risk, and the NIH’s National Center for Complementary and Integrative Health advises stopping it and seeing a doctor if you notice signs of liver trouble.

🪴 Sage and 🌱 soy: a little more promising

Sage (Salvia officinalis) has been used for excessive sweating for a long time. In a 2011 study, 71 women took a fresh sage tablet daily for eight weeks, and their hot flashes dropped substantially. The catch is that there was no placebo group, and given how strong the placebo effect is for hot flashes, that result cannot be called proof. It is a reasonable, low-risk thing to try as a culinary herb or tea.

Soy isoflavones, plant compounds with weak estrogen-like activity, have been studied far more. Some meta-analyses have found a modest reduction in hot flash frequency over placebo. Others have not, and The Menopause Society judged the evidence too inconsistent to recommend them. Eating soy foods such as tofu, edamame and soy milk is safe for most women and good for overall diet quality. Women with a history of hormone-sensitive cancer should ask their oncologist before taking concentrated isoflavone supplements.

🧠 What actually has strong evidence

The Menopause Society’s 2023 guidance is clear about what does work without hormones:

• Cognitive behavioral therapy (CBT). It does not stop hot flashes, but it reduces how much they bother you and how much they disrupt sleep.
• Clinical hypnosis. Trials found real reductions in hot flash frequency and severity.
• Certain antidepressants (SSRIs and SNRIs) and gabapentin. These prescription medicines reduce hot flashes even in women who are not depressed.
• Fezolinetant. A newer prescription drug approved by the FDA in 2023 that targets the brain pathway behind hot flashes.

And for many healthy women under 60 or within about ten years of their last period, hormone therapy remains the most effective treatment. Whether it is right for you depends on your personal health history, so it is a conversation worth having with your doctor rather than ruling it out based on old headlines.

Simple habits that help

• Keep the bedroom cool and use layers you can shed quickly.
• Notice your triggers. Alcohol, spicy food, hot drinks and stress set off hot flashes for many women.
• Stay active. Exercise has mixed evidence for hot flashes themselves but clear benefits for sleep, mood, bones and heart, all of which matter more after menopause.
• Do not smoke. Smokers tend to have more frequent hot flashes.

Who should talk to a doctor first

• Anyone with liver disease, or who drinks heavily, before trying black cohosh.
• Women with a history of breast, uterine or ovarian cancer. Ask your oncologist before any menopause supplement.
• Anyone on prescription medication, including blood thinners, antidepressants or tamoxifen, since herbs can interact.
• Anyone with bleeding after menopause. Vaginal bleeding a year or more after your last period always needs a medical check.

The honest bottom line

Black cohosh is the best-known herbal remedy for hot flashes, but the strongest reviews and the longest trial found it works no better than a placebo, and it carries a small risk to the liver. Sage and soy are lower-risk ideas with weak to mixed evidence. If hot flashes are wrecking your sleep or your days, the treatments with real evidence, from CBT and hypnosis to prescription non-hormone drugs and hormone therapy, are worth a frank conversation with your doctor.

Studies and sources

• Leach MJ, Moore V (2012). Black cohosh (Cimicifuga spp.) for menopausal symptoms. Cochrane Database of Systematic Reviews.
• Newton KM et al. (2006). Treatment of vasomotor symptoms of menopause with black cohosh, multibotanicals, soy, hormone therapy, or placebo. Annals of Internal Medicine, via PubMed.
• The 2023 nonhormone therapy position statement of The North American Menopause Society. Menopause.
• Black cohosh: usefulness and safety. NCCIH.
• Black cohosh: fact sheet for health professionals. NIH Office of Dietary Supplements.
• Bommer S, Klein P, Suter A (2011). First time proof of sage’s tolerability and efficacy in menopausal women with hot flushes. Advances in Therapy, via PubMed.

This article is for general education and is not medical advice. Talk to your doctor or pharmacist before starting a supplement, especially if you take medication or have a health condition. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.