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evidence · mechanism · dose
Supplements/Compound

Soy Isoflavones

aka Genistein · Daidzein · Equol

Phytoestrogens with mild SERM effects on bone, hot flashes, and lipids.

Women's HealthBone HealthCardiovascular Health

Overview

Phytoestrogens with mild SERM effects on bone, hot flashes, and lipids.

Natural sources
  • Soybeans
  • Tofu
  • Tempeh
Common forms
  • Standardized isoflavones
  • S-equol

Mechanism of action

Bind ER-β preferentially; ~30% of people convert daidzein to equol via gut microbes.

Pathways
  • · ER-β modulation

Effects on the body

Decreases
Hot flashes
Supports
Bone density

Organ system effects

Bones

Maintains BMD in postmenopausal women.

Evidence-based benefits

Reduces hot flash frequency

Moderate evidence

Preserves BMD

Moderate evidence

Potential side effects

Common
  • · GI upset
Rare
    Serious

      Drug interactions

      Tamoxifen
      Uncertain interaction.
      moderate
      Levothyroxine
      Reduces absorption.
      moderate

      Supplement interactions

      Pairs well with

      None listed.

      Avoid combining with

      No specific avoidances listed.

      Dosing & bioavailability

      Typical dose
      40–80 mg isoflavones

      Where to buy

      Affiliate-style search links to reputable retailers. We don't endorse specific brands — verify third-party testing (USP, NSF, Informed Sport) before purchase.

      Compound
      Soy Isoflavo…
      Amazon
      Wide selection · fast shipping
      Compound
      Soy Isoflavo…
      iHerb
      Global delivery · curated brands
      Compound
      Soy Isoflavo…
      Thorne
      Practitioner-grade · NSF tested

      Scientific evidence (9)

      Meta-analysisMenopause · 2012

      Soy isoflavones and vasomotor symptoms

      Taku K, et al.

      Meta-analysis of 19 RCTs of soy isoflavones.

      Key findings

      Significant reduction in hot-flash frequency and severity.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Soy Isoflavones — Reduces hot flash frequency

      Live PubMed search

      Live results for "Soy Isoflavones Reduces hot flash frequency" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Soy Isoflavones and "Reduces hot flash frequency". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Soy Isoflavones — Preserves BMD

      Live PubMed search

      Live results for "Soy Isoflavones Preserves BMD" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Soy Isoflavones and "Preserves BMD". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Soy Isoflavones — randomized controlled trial

      Live PubMed search

      Live results for "Soy Isoflavones randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Soy Isoflavones and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Soy Isoflavones — meta-analysis

      Live PubMed search

      Live results for "Soy Isoflavones meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Soy Isoflavones and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Soy Isoflavones — pharmacokinetics

      Live PubMed search

      Live results for "Soy Isoflavones pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Soy Isoflavones and "pharmacokinetics". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Soy Isoflavones — safety adverse events

      Live PubMed search

      Live results for "Soy Isoflavones safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Soy Isoflavones and "safety adverse events". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Soy Isoflavones — dose response

      Live PubMed search

      Live results for "Soy Isoflavones dose response" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Soy Isoflavones and "dose response". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewGoogle Scholar · 1970

      Google Scholar: Soy Isoflavones — clinical evidence

      Live Scholar search

      Cross-database citation index for Soy Isoflavones as it relates to "clinical evidence".

      Key findings

      Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

      Open study
      Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.