Copyright © 2021 Natural Medicines (
June 2013

Isoflavones May Reduce Menopausal Symptoms

Various isoflavones have been studied for therapeutic effects in women with menopause.

Isoflavones were first discovered due to their ability to disrupt the action of estrogen in animals. As a result, they are classified as a type of phytoestrogen, which, as the name suggests, is a naturally occurring plant ("phyto") chemical with estrogen-like properties. In the diet, isoflavones may be found in soybeans; soy-based foods, including soy milk, flour, nuts, tempeh, and tofu; and legumes, such as peas, peanuts, chick peas, and navy beans.

Sequol, a daidzein (a soy isoflavone) metabolite, may improve certain menopausal symptoms. According to several well-designed clinical trials, sequol decreased the number and severity of daily hot flashes. Furthermore, sequol decreased joint and muscle pain, neck and muscle stiffness, mood as well as crow's feet wrinkles in multiple studies.

Daidzein, prior to absorption, has also been studied in menopausal women, but with mixed results. Some studies showed a decrease in hot flash frequency, improved sexuality and reduced hot flash severity, as well as improved bone health, quality of life and cholesterol. However, other studies found that daidzein lacked effects on bone and heart health, vaginal and menopausal symptoms, and brain function.

Finally, genistein has been studied with conflicting results. Some studies reported beneficial results for heart health, hot flashes, skeletal health and even blood sugar. Conversely, many other trials found inconclusive or temporary results when measuring these same parameters.

Overall, researchers continue to reiterate the need for further exploration, larger trials, safety and efficacy studies and more studies in differing populations.

For more information about isoflavones and their effect on menopause, please visit Natural Standard's Foods, Herbs & Supplements Database.


  1. Evans M, Elliott JG, Sharma P, Berman R, Guthrie N. The effect of synthetic genistein on menopause symptom management in healthy postmenopausal women: a multi-center, randomized, placebo-controlled study. Maturitas. 2011 Feb;68(2):189-96. 
  2. Jenks BH, Iwashita S, Nakagawa Y, Ragland K, Lee J, Carson WH, Ueno T, Uchiyama S. A pilot study on the effects of S-equol compared to soy isoflavones on menopausal hot flash frequency. Womens Health (Larchmt). 2012 Mar;21(6):674-82. 
  3. Jou HJ, Wu SC, Chang FW, Ling PY, Chu KS, Wu WH. Effect of intestinal production of equol on menopausal symptoms in women treated with soy isoflavones. Int J Gynaecol Obstet. 2008 Jul;102(1):44-9. 
  4. Kreijkamp-Kaspers S, Kok L, Grobbee DE, de Haan EH, Aleman A, Lampe JW, van der Schouw YT. Effect of soy protein containing isoflavones on cognitive function, bone mineral density, and plasma lipids in postmenopausal women: a randomized controlled trial. JAMA. 2004 Jul;292(1):65-74. 
  5. Natural Standard: The Authority on Integrative Medicine.
  6. Oyama A, Ueno T, Uchiyama S, Aihara T, Miyake A, Kondo S, Matsunaga K. The effects of natural S-equol supplementation on skin aging in postmenopausal women: a pilot randomized placebo-controlled trial. Menopause. 2012 Feb;19(2):202-10. 

The information in this brief report is intended for informational purposes only, and is meant to help users better understand health concerns. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions. Copyright © 2021 Natural Medicines Inc. Commercial distribution or reproduction prohibited. Natural Medicines is the leading provider of high-quality, evidence-based, clinically-relevant information on natural medicine, dietary supplements, herbs, vitamins, minerals, functional foods, diets, complementary practices, CAM modalities, exercises and medical conditions. Monograph sections include interactions with herbs, drugs, foods and labs, contraindications, depletions, dosing, toxicology, adverse effects, pregnancy and lactation data, synonyms, safety and effectiveness.