Evidence explainerMenopause & Perimenopause

Menopause Supplements vs Placebo: Black Cohosh, Soy and the Blends Sold on Instagram

Black cohosh did no better than placebo for hot flashes in pooled trials. Soy isoflavones did modestly better, yet experts still do not recommend them. Brand-name blends have no published trials we could find.

By Kymata Health editorial teamPublished October 10, 2026Last verified October 10, 2026

Medical review pending. Written by our editorial team from the studies and documents cited below; a credentialed clinician has not reviewed it yet. Educational only, not medical advice.

Key takeaways

  • A Cochrane review of 16 trials (2,027 women) found no difference between black cohosh and placebo in hot flash frequency [1].
  • In the same review, hormone therapy reduced menopausal symptom scores more than black cohosh [1].
  • A meta-analysis of 13 trials found soy isoflavones (median 54 mg/day) cut hot flash frequency by about 21% vs placebo, with large differences between studies [2].
  • The 2023 nonhormone position statement still does not recommend supplements, herbal remedies or soy extracts for hot flashes [3].
  • Hormone therapy remains the most effective treatment for hot flashes [4].

Black cohosh: the most-studied herb, and a null result

The Cochrane review pooled 16 randomized trials of oral black cohosh at a median 40 mg/day for about 23 weeks [1]. Against placebo there was no significant difference in daily hot flashes (mean difference 0.07 per day, 3 trials, 393 women) or in menopausal symptom scores (4 trials) [1].

The reviewers rated the safety evidence inconclusive because adverse events were poorly reported [1]. Black cohosh products also vary in species, extract and dose, so one brand's label says little about another's. Our black cohosh monograph covers forms, doses and liver-safety reports.

Soy isoflavones: a modest signal

A 2012 meta-analysis of randomized trials found soy isoflavone supplements (median 54 mg/day aglycone equivalents, 6 weeks to 12 months) reduced hot flash frequency by 20.6% and severity by 26.2% compared with placebo [2]. Heterogeneity was high, and products with more genistein did better [2].

The 2023 position statement weighed the broader evidence and listed soy foods, soy extracts and the soy metabolite equol as not recommended for hot flashes (Level II) [3]. Our soy isoflavones monograph covers doses and food sources.

Brand-name menopause blends

Many popular menopause products combine several herbs with vitamins in one capsule. We could not find a published randomized trial of any finished brand-name blend named in this hub in PubMed (searched October 10, 2026), so their effect is unknown beyond what single ingredients show.

If a supplement promises to "balance hormones", ask what it was tested against and for how long. If the answer is a customer survey or an unpublished study, treat the claim as marketing.

What has better evidence

For hot flashes: hormone therapy [4], or the options in our non-hormonal treatment guide [3]. For sleep, our 3 a.m. waking guide covers what has been tested. For muscle and bone after 40, see creatine for women over 40.

Quick answers

Is black cohosh dangerous?

The Cochrane review found the safety data inconclusive because trials reported side effects poorly [1]. Tell your clinician if you take it, especially with liver disease or other medicines.

Should I eat more soy?

Soy foods are fine as food, but the 2023 position statement does not recommend soy foods or extracts as a hot flash treatment [3].

More in Menopause & Perimenopause

References

  1. [1]Black cohosh (Cimicifuga spp.) for menopausal symptoms. Cochrane Database Syst Rev, 2012. PMID 22972105
  2. [2]Extracted or synthesized soybean isoflavones reduce menopausal hot flash frequency and severity: systematic review and meta-analysis of randomized controlled trials. Menopause, 2012. PMID 22433977
  3. [3]The 2023 nonhormone therapy position statement of The North American Menopause Society. Menopause, 2023. PMID 37252752
  4. [4]The 2022 hormone therapy position statement of The North American Menopause Society. Menopause, 2022. PMID 35797481

Dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Prescription options need a licensed clinician. Talk to your clinician or pharmacist before starting anything new, especially if you take prescription medicines, are pregnant or breastfeeding.

Keep reading: Menopause and HRT

Menopause and HRT: every page →Women's hormone telehealth compared →Browse all topics →

Previous in this topicCan't or Won't Take Hormones? The Non-Hormonal Hot Flash Treatments That Beat PlaceboTwo new brain-targeted pills, an older list of repurposed drugs, and behavioral therapy all have trial data for hot flashes.Next in this topicBest Peptides for Women Over 40: Menopause, Fat Loss, Sleep & SkinEvidence-based guide to peptides for women over 40 - menopause weight gain, sleep disruption, skin aging, libido, and which peptides address each.Peptides for Women's Health: Hormones, Hair, and HealingWomen-specific peptide protocols are underrepresented in the literature.Estrogen Patch vs Gel vs Pill for MenopauseOral and through-the-skin (transdermal) estrogen relieve hot flashes about equally well in studies.Progesterone in HRT: Micronized vs SyntheticIf you have a uterus and take systemic estrogen, you need a progestogen to protect the uterine lining: in the PEPI trial, estrogen alone caused endometrial hyperplasia that the…

Menopause treatment cost →3 a.m. waking in menopause →Also in: Supplements and vitamins