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NCCIH Clinical Digest

for health professionals

Menopausal Symptoms and Complementary Health Approaches: What the Science Says

February 2021

Clinical Guidelines, Scientific Literature, Info for Patients: 
Menopausal Symptoms and Complementary Health Approaches


Soy isoflavone supplements or soy protein may help to reduce the frequency and severity of menopausal hot flashes, but the effect may be small.

What Does the Research Show?

  • A 2016 systematic review and meta-analysis of 62 studies involving 6,653 women found that specific phytoestrogen supplementations, such as soy isoflavones, were associated with modest reductions in the frequency of hot flashes and vaginal dryness but no significant reduction in night sweats. However, many of the studies included in the review were of low quality.
  • A 2018 systematic review and meta-analysis found that soy showed no significant effect on sexual function in menopausal women.


  • Although information on adverse effects is limited, soy extracts appear to be generally safe when taken for short periods of time. However, long-term use of soy extracts (which contain phytoestrogens) has been associated with thickening of the lining of the uterus.
  • Current evidence indicates that it’s safe for women who have had breast cancer or who are at risk for breast cancer to eat soy foods. However, it’s uncertain whether soy isoflavone supplements are safe for these women.

Black Cohosh

Research suggests that certain black cohosh extracts and some combination products containing black cohosh may reduce some menopause symptoms. Most of the research has been on the single extract Remifemin. Research on other black cohosh products has had inconsistent results. Guidelines released in 2015 indicate that there is a lack of consistent evidence for any benefit from black cohosh for menopause symptoms. But a 2017 review of research suggests that black cohosh extracts approved for treatment in Europe seem to decrease menopause symptoms.

What Does the Research Show?

  • A 2016 review found that there is no high-quality, consistent evidence that black cohosh benefits patients with menopausal symptoms more than placebo.
  • A 2017 systematic review and meta-analysis of 47 randomized controlled trials involving a total of 8,326 women with menopausal symptoms found that black cohosh was more effective than placebo in reducing vasomotor symptoms, but not significantly better than transdermal estradiol and progestogen.


  • In clinical trials, people have taken black cohosh for as long as 12 months with no serious harmful effects.
  • Black cohosh can cause some mild side effects, such as stomach upset, cramping, headache, rash, a feeling of heaviness, vaginal spotting or bleeding, and weight gain.
  • Some commercial black cohosh products have been found to contain the wrong herb or to contain mixtures of black cohosh and other herbs that are not listed on the label.
  • Cases of liver damage—some very serious—have been reported in people taking commercial black cohosh products. These problems are rare, and it is uncertain whether black cohosh was responsible.
  • The risk of interactions between black cohosh and medicines appears to be small. Preliminary laboratory research, some of it supported by NCCIH, suggests that black cohosh might affect statin medicines, which are used to reduce blood cholesterol levels.
  • It’s not clear if black cohosh is safe for women who have had hormone-sensitive conditions such as breast cancer.

Red Clover

Studies on the effects of red clover on menopause symptoms, such as hot flashes, and on blood levels of cholesterol and other lipids have had inconsistent results.

What Does the Research Show?

  • A 2016 systematic review and meta-analysis found that red clover significantly improved vaginal dryness and vaginal atrophy, but showed less therapeutic effect on psychology status, sexual problems, and sleeping disorders. The review concluded that red clover consumption may decrease frequency of hot flashes, especially in women with severe hot flashes (5 or more per day).
  • A 2017 parallel, double blind, randomized control trial of 62 perimenopausal women aged 40 to 65, reporting 5 or more hot flushes per day and follicle stimulating hormone 35 or more IU/L, examined the effects of red clover extract combined with probiotics, compared with placebo, on vasomotor symptoms (i.e., hot flashes and night sweats). Results of the study suggest that moderate doses of red clover extract were more effective and superior to placebo in reducing physiological and self-reported vasomotor symptoms.
  • A 2018 systematic review and meta-analysis found that red clover showed no significant effect on sexual function in menopausal women.


  • Red clover extracts have been used in clinical studies for as long as 3 years with apparent safety.
  • There are some concerns that red clover, which also contains phytoestrogens, might have harmful effects on hormone-sensitive tissue.


Studies have had conflicting results on whether flaxseed helps with symptoms of menopause.

What Does the Research Show?

  • 2018 systematic review and meta-analysis found that flaxseed showed no significant effect on sexual function in menopausal women.
  • 2012 randomized controlled trial involving 90 postmenopausal women found that after 6 months of treatment, flaxseed was effective in reducing menopausal symptoms when comparing the beginning and end of the treatment using the paired t-test. However, when an analysis in variance was done, comparing flaxseed treatment with placebo, no significant differences were found.
  • 2012 randomized controlled trial involving 188 postmenopausal women found that after 6 weeks of treatment with flaxseed or placebo, there was no significant difference in reduction of hot flashes between the groups.


  • Don’t eat raw or unripe flaxseeds, which may contain potentially toxic compounds.
  • Flaxseed and flaxseed oil supplements seem to be well tolerated in limited amounts. Few side effects have been reported.
  • Flaxseed, like any fiber supplement, should be taken with plenty of water, as it could worsen constipation or, in rare cases, cause an intestinal blockage. Both flaxseed and flaxseed oil can cause diarrhea.


There is some evidence that yoga may reduce menopausal symptoms, but the effect is similar to other exercise interventions.

What Does the Research Show?

  • A 2018 meta-analysis and systematic review of 13 randomized controlled trials involving 1,306 participants found that compared with no treatment, yoga reduced total menopausal symptoms including psychological, somatic, vasomotor, and urogenital symptoms. However, compared with exercise controls, only an effect on vasomotor symptoms was found.
  • A 2010 review of 21 papers assessed mind and body therapies for menopausal symptoms. The researchers found that yoga, tai chi, and meditation-based programs may be helpful in reducing common menopausal symptoms including the frequency and intensity of hot flashes, sleep and mood disturbances, stress, and muscle and joint pain.


  • Overall, clinical trial data suggest yoga as taught and practiced in these research studies under the guidance of skilled teacher has a low rate of minor side effects. It is not uncommon for practitioners to have some minor, transient discomfort, like in most physical activity programs.
  • However, injuries from yoga, some of them serious, have been reported in the popular press.
  • People with health conditions should work with an experienced teacher who can help modify or avoid some yoga poses to prevent side effects.


There is some evidence suggesting that hypnosis may help improve certain menopausal symptoms, such as hot flashes. A 2015 position paper from the North American Menopause Society recommended hypnosis for managing hot flashes but acknowledged that favorable evidence is limited.

What Does the Research Show?

  • A 2013 randomized controlled trial in 187 postmenopausal women found that clinical hypnosis significantly reduced self-reported and physiologically measured hot flashes. Although the mechanism of how clinical hypnosis works is unknown, the women in this same study who practiced hypnosis had significantly greater levels of satisfaction than the control group. A 2008 randomized trial found that hypnosis appears to reduce perceived hot flashes in breast cancer survivors and may have additional benefits such as improved mood and sleep.


  • Hypnosis is considered safe when performed by a health professional trained in hypnotherapy. Self-hypnosis also appears to be safe for most people. There are no reported cases of injury resulting from self-hypnosis.
  • Meditation is considered to be safe for healthy people. There have been rare reports that meditation could cause or worsen symptoms in people who have certain psychiatric problems, but this question has not been fully researched.


Results of studies have been inconsistent as to whether acupuncture is beneficial for menopausal symptoms.

What Does the Research Show?

  • A 2017 meta-analysis and systematic review of 13 randomized controlled trials involving 844 breast cancer patients found that acupuncture significantly alleviated menopause symptoms, but had no effect on hot flashes.
  • A 2016 pragmatic, randomized controlled trial involving 209 perimenopausal and postmenopausal women aged 45 to 60 years found that a course of acupuncture treatments was associated with significant reduction in vasomotor symptoms and several quality-of-life measures, compared with no acupuncture, and that clinical benefit persisted for at least 6 months beyond the end of treatment. Statistically significant clinical improvement was observed after three acupuncture treatments, and maximal clinical effects occurred after a median of eight treatments.
  • A 2018 randomized controlled trial involving a total of 360 women with menopause-related symptoms found that 8 weeks of electroacupuncture treatment did not seem to relieve menopausal symptoms, even though it appeared to improve participants’ quality of life.
  • A 2013 Cochrane systematic review of 16 randomized controlled trials involving a total of 1,155 women found that compared to sham acupuncture, there was no evidence of any difference in their effect on hot flashes. When acupuncture was compared with no treatment, there appeared to be a benefit from acupuncture, but acupuncture appeared to be less effective than hormone therapy.


  • Relatively few complications from the use of acupuncture have been reported to the U.S. Food and Drug Administration (FDA), in light of the millions of people treated each year and the number of acupuncture needles used. Still, complications have resulted from inadequate sterilization of needles and from improper delivery of treatments.
  • When not delivered properly, acupuncture can cause serious adverse effects, including infections and punctured organs.


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Chien T-J, Hsu C-H, Liu C-Y, et al. Effect of acupuncture on hot flush and menopause symptoms in breast cancer—a systematic review and meta-analysis. PLoS One. 2017;12(8):e0180918.

Colli MC, Bracht A, Soares AA, et al. Evaluation of the efficacy of flaxseed meal and flaxseed extract in reducing menopausal symptoms. J Med Food. 2012;15(9):840-845.

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Najafi MN, Ghazanfarpour M. Effect of phytoestrogens on sexual function in menopausal women: a systematic review and meta-analysis. Climacteric. 2018;21(5):437-445.

Pruthi S, Qin R, Terstreip SA, et al. A phase III, randomized, placebo-controlled, double-blind trial of flaxseed for the treatment of hot flashes: North Central Cancer Treatment Group N08C7. Menopause. 2012;19(1):48-53.

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Tandrup Lambert MN, Thorup AC, Szoscka Hansen ES, et al. Combined red clover isoflavones and probiotics potently reduce menopausal vasomotor symptoms. PLoS One. 2017;12(6):e0176590.

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