Treatments and supplements · Phytoestrogens and isoflavones

Do soy and plant oestrogens help with menopause?

What we can tell you today: how thoroughly this has been studied.

Well studied

14 studies, including one that brings together the results of several trials in people.

5 Repeated evidence 1 study

4 Large controlled trial 10 studies

3 Small study in people 3 studies

This says how thoroughly something has been studied — not whether it works for you. What each study actually found is in the study itself, and in the plain-language write-ups we are adding.

Appears under: Menopause and hormones · Skin aging · Hair and nails

The studies

5 Repeated evidence Effect of Soy Isoflavones on Measures of Estrogenicity: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
2025 · Advances in nutrition (Bethesda, Md.) · 3,285 participants · manufacturer helped fund this
4 Large controlled trial Soy isoflavones in the prevention of menopausal bone loss and menopausal symptoms: a randomized, double-blind trial.
2011 · Archives of internal medicine · 2,009 participants
4 Large controlled trial The effect of a randomized 12-week soy drink intervention on everyday mood in postmenopausal women.
2020 · Menopause (New York, N.Y.) · 101 participants
4 Large controlled trial A pilot study on the effects of S-equol compared to soy isoflavones on menopausal hot flash frequency.
2012 · Journal of women's health (2002) · 102 participants
4 Large controlled trial Phytoestrogen supplements for the treatment of hot flashes: the Isoflavone Clover Extract (ICE) Study: a randomized controlled trial.
2003 · JAMA · 252 participants
4 Large controlled trial Effects of the phytoestrogen genistein on hot flushes, endometrium, and vaginal epithelium in postmenopausal women: a 2-year randomized, double-blind, placebo-controlled study.
2009 · Menopause (New York, N.Y.) · 389 participants
4 Large controlled trial Daidzein-rich isoflavone aglycones are potentially effective in reducing hot flashes in menopausal women.
2008 · Menopause (New York, N.Y.) · 147 participants
4 Large controlled trial Nonhormonal management of postmenopausal women: effects of a red clover based isoflavones supplementation on climacteric syndrome and cardiovascular risk serum profile.
2014 · Clinical and experimental obstetrics & gynecology · 150 participants
4 Large controlled trial Design and baseline characteristics of the soy phytoestrogens as replacement estrogen (SPARE) study--a clinical trial of the effects of soy isoflavones in menopausal women.
2011 · Contemporary clinical trials · 283 participants
4 Large controlled trial Soy isoflavones and melatonin for the relief of climacteric symptoms: a multicenter, double-blind, randomized study.
2004 · Maturitas · 262 participants
4 Large controlled trial [Efficacy of standardized isoflavones extract (Soyfem) (52-104 mg/24h) in moderate and medium-severe climacteric syndrome].
2007 · Ginekologia polska · 169 participants
3 Small study in people Soy Protein Containing Isoflavones Improves Facial Signs of Photoaging and Skin Hydration in Postmenopausal Women: Results of a Prospective Randomized Double-Blind Controlled Trial.
2023 · Nutrients
3 Small study in people The Women's Study for the Alleviation of Vasomotor Symptoms (WAVS): a randomized, controlled trial of a plant-based diet and whole soybeans for postmenopausal women.
2021 · Menopause (New York, N.Y.) · 38 participants · manufacturer helped fund this
3 Small study in people The effects of soy protein containing phytoestrogens on menopausal symptoms in postmenopausal women.
2002 · Climacteric : the journal of the International Menopaus