Most women tolerate black cohosh well. The side effects reported most often are mild and short-lived, like an upset stomach or a rash, and in clinical trials they showed up at rates similar to placebo. Here’s what to expect, the one rare issue worth knowing about, and how to try it sensibly. Black cohosh is one of the herbs in She+ by Immunotec, the perimenopause product I use.
Disclosure: My husband, Brandon, does freelance marketing work for Immunotec, the company that makes She+. I got She+ free as an early tester.
- Black cohosh has been used safely in studies lasting up to a year and is generally well tolerated.
- The most common side effects are mild, temporary stomach upset and rash.
- In a 2023 meta-analysis of 22 studies, women dropped out of black cohosh groups at about the same rate as placebo groups.
- Rare liver problems have been reported, with no proven cause. Stop and call your doctor if you notice yellowing skin, dark urine or belly pain.
- Skip it if you have liver disease, are pregnant or breastfeeding, or have a history of breast or uterine cancer, unless your doctor says otherwise.
The short answer: most women do fine
Black cohosh is one of the most studied herbs for menopause, and that’s good news when it comes to side effects, because there’s a lot of data to look at. According to the National Center for Complementary and Integrative Health, black cohosh has been used safely in research studies that lasted as long as a year and is generally well tolerated (NCCIH).
The NIH Office of Dietary Supplements describes a low rate of side effects in clinical trials. The most commonly reported are stomach upset and rashes, which it describes as mild and transient (NIH ODS).
The big trial reviews point the same way. A 2023 meta-analysis of 22 studies with 2,310 women found that the dropout rate for black cohosh was similar to placebo (Menopause, 2023). A 2021 review of one widely used extract, covering 35 clinical studies, reported few minor side effects, at rates comparable to placebo (Climacteric, 2021). Some of that review’s authors work for the extract’s maker, so keep that in mind, but it lines up with the government fact sheets.
Side effects women report
Upset stomach
Most commonMild stomach upset is the side effect mentioned most often, and it tends to be temporary (NIH ODS). Taking your supplement with food is a simple first step if your stomach is sensitive.
Rash
Mild, short-livedSkin rash is the other commonly reported effect, also described as mild and transient (NIH ODS). If you get hives, swelling or any trouble breathing, stop and get medical help right away, as you would with any new product.
Nausea, dizziness or headache
Mostly at high amountsMemorial Sloan Kettering Cancer Center lists nausea, dizziness, vomiting and headache mainly with higher-than-normal amounts (MSK). That’s a good reason to stick with the amount on the label rather than doubling up.
Breast tenderness, spotting, aches
Similar to placeboTrials have also recorded breast pain, vaginal spotting and muscle or joint complaints, but these happened at about the same rate as in women taking placebo (NIH ODS). Any new or unexpected bleeding is still worth a call to your doctor, since it can have other causes.
A calm word about the liver
You may have read that black cohosh can affect the liver. Here’s what the experts actually say. There have been rare reports of liver problems in people taking products labeled as black cohosh, some of them serious, but it hasn’t been shown that black cohosh caused them. Some products have turned out to contain the wrong herb or unlisted mixtures, which is one possible explanation (NCCIH; NIH ODS). In the 2015 sleep trial, researchers checked liver function every three months for six months and found no adverse events tied to black cohosh (Climacteric, 2015). The sensible rule: if you ever notice yellowing skin, dark urine, belly pain or unusual tiredness, stop taking it and call your doctor.
Who should skip it or ask first
- Liver disease. If you have a liver condition, the U.S. Pharmacopeia advises avoiding black cohosh (NIH ODS).
- Pregnancy or breastfeeding. Black cohosh may not be safe during pregnancy or while breastfeeding (NCCIH).
- Breast or uterine cancer history. It’s uncertain whether black cohosh is safe after hormone-sensitive conditions like breast or uterine cancer (NCCIH). MSK notes it may interfere with tamoxifen, so talk with your oncologist first (MSK).
- Prescription medicines. Some herbs and medicines interact, so check with your doctor or pharmacist if you take anything regularly (NCCIH). If your product also contains ginger, mention it if you take a blood thinner like warfarin (BJCP, 2020).
- Blue cohosh is different. Blue cohosh is a separate herb with its own risks. Make sure the label says black cohosh (NCCIH).
Why women still reach for it
Side effects only matter in context, and the reason so many women try black cohosh is that the research on benefits is encouraging. The 2023 meta-analysis found improvements in hot flashes and overall menopause symptoms compared with placebo (Menopause, 2023). A six-month sleep lab trial found women on black cohosh spent 15.8% less time awake after falling asleep (Climacteric, 2015). I go deeper in my main black cohosh guide.
For me, it’s part of She+, the jelly stick I reviewed here, which pairs black cohosh with red clover, ginger and glucomannan in an apple blueberry jelly stick. I started it about two months ago after magnesium didn’t help my sleep. My Oura sleep scores went from what looked like waking every ten minutes to the 80s and 90s, my energy came back, and my hot flashes have eased a lot. I share the whole story in my She+ review. Individual results vary.
How to try black cohosh sensibly
| Pick a reputable brand | Since mislabeled products are one suspected cause of problems, buy from a company you trust and check that the label says black cohosh (Actaea or Cimicifuga racemosa). |
|---|---|
| Stick to the label amount | Studies have used a range of daily amounts, with 40 mg a day a common middle point (NIH ODS). More isn’t better. |
| Take it with food | An easy way to sidestep mild stomach upset. |
| Track how you feel | Jot down hot flashes, sleep and any side effects for a few weeks so you can see real patterns. |
| Tell your doctor | Especially if you take prescription medicines or have any of the conditions above. |
| Know your stop signs | Yellowing skin, dark urine, belly pain, or a rash with swelling: stop and call. |
If black cohosh isn’t right for you, there are plenty of other paths. See my roundups of herbal remedies for hot flashes and natural remedies for menopause, and the full perimenopause symptoms list. Prescription options such as hormone therapy, fezolinetant (Veozah), low-dose antidepressants and gabapentin are also worth discussing with your doctor (Mayo Clinic).
Frequently asked questions
What are the most common side effects of black cohosh?
Mild, temporary stomach upset and rash are the ones reported most often. Many women notice no side effects at all.
Is black cohosh bad for your liver?
Liver problems have been reported rarely in people taking black cohosh products, but a cause hasn’t been proven. If you have liver disease, skip it. Anyone taking it should stop and call a doctor if they notice yellowing skin, dark urine or belly pain.
Can black cohosh cause weight gain?
Weight gain isn’t listed among the side effects reported in the NIH fact sheet. Weight changes are common in perimenopause for other reasons, which I cover in perimenopause weight gain.
How long can you take black cohosh?
It has been used safely in studies lasting up to a year. Check in with your doctor if you plan to take it longer.
Does black cohosh interact with medications?
It isn’t known to have many clinically important interactions, but this hasn’t been studied thoroughly, and MSK flags tamoxifen and some chemotherapy drugs. Always check with your pharmacist.
Sources
- Black cohosh: usefulness and safety. National Center for Complementary and Integrative Health. NCCIH
- Black cohosh fact sheet for health professionals. NIH Office of Dietary Supplements. NIH ODS
- Black cohosh extracts in women with menopausal symptoms: an updated pairwise meta-analysis. Menopause, 2023. PubMed
- Review and meta-analysis: isopropanolic black cohosh extract iCR for menopausal symptoms. Climacteric, 2021. PubMed
- Black cohosh improves objective sleep in postmenopausal women with sleep disturbance. Climacteric, 2015. PubMed
- Black cohosh. Memorial Sloan Kettering Cancer Center, About Herbs. MSK
- Warfarin and food, herbal or dietary supplement interactions: a systematic review. Br J Clin Pharmacol, 2020. PubMed
- Hot flashes: diagnosis and treatment. Mayo Clinic. Mayo Clinic
Denise Walsh
Michigan woman in perimenopause, writing about what’s actually helped her sleep, energy and hot flashes.
Jesse Ovlasuk, RN
ICU registered nurse in Grand Rapids. Reviews every post for medical accuracy and safety.
This article reflects one person’s experience and is for general information only. It is not medical advice. Talk with your healthcare provider before starting any supplement.