We use essential cookies (authentication, your saved goals/stack) by default. With your permission we’ll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies
Soy Isoflavones
Plant compounds with weak estrogenic effects that support menopausal symptoms, bone health, and cardiovascular function.
What the evidence says
Soy Isoflavones appears to help in 8 of 10 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 1992–2026 with a typical study size of 1,840 participants.
Based on 279 studies · 54 meta-analyses · 203 RCTs · 965,745 total participants
Confidence
High confidenceWhat the studies found
By outcome
A large meta-analytic base shows real but modest benefits for hot flashes, spine bone density, and LDL, held to Moderate by small effect sizes, heterogeneity, and inconsistent results across outcomes.
12 trials ongoing or recruiting · 106 completed on ClinicalTrials.gov
19 of the completed trials have posted results
Registered trials show research momentum for Soy Isoflavones, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Oct 2026
Under EU law (Reg. 1924/2006), EFSA reviews whether a specific health claim for Soy Isoflavones meets the evidence standard. These are independent regulatory decisions on claims — not studies, and never counted toward the evidence score above.
“Not authorised” means the specific claim wording did not meet the EU’s evidence standard — often a matter of dossier or phrasing, not proof of no effect. EFSA judges marketing claims and is kept separate from our study-based evidence score.
Source: EU Register of nutrition and health claims (European Commission / EFSA) · register snapshot Feb 2013
Soy Isoflavones are a class of phytoestrogens found in soybeans, including genistein, daidzein, and glycitein. These compounds bind to estrogen receptors with weak activity, potentially providing benefits without the risks of hormone therapy.
Extensive research supports their use for hot flashes, bone health maintenance, and cardiovascular support.
Weak binding to estrogen receptors, especially ER-beta
Scavenges free radicals and reduces oxidation
Helps maintain bone formation over resorption
How Soy Isoflavones works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Consult healthcare provider; dietary soy is generally safe
Discuss concentrated isoflavone supplements with the oncology team. Soy foods and concentrated supplements are separate questions, and cancer outcomes are a separate question from menopausal symptom relief.
Theoretical interference with anti-estrogen therapy, not measured in human studies. Discuss concentrated isoflavone supplements with the oncology team.
Reduces levothyroxine absorption and is goitrogenic; separate doses and monitor TSH
Additive estrogenic effects
Theoretical interference with aromatase inhibitor therapy, not measured in people. Avoid concentrated isoflavone supplements unless the oncology team agrees. Dietary soy is a separate question. This precaution has no severity grade. The size of any effect for this product has not been established, so it is shown for you to raise with a pharmacist, not as an assessed risk or an all-clear. Do not stop or change prescribed medicines based on this notice.
Tip: Take with food; start with lower dose
Tip: Reduce dose; may resolve with time
Soy Isoflavones has an evidence score of 6/10 — moderate evidence based on 279 indexed studies, including 31 meta-analyses. Plant compounds with weak estrogenic effects that support menopausal symptoms, bone health, and cardiovascular function. Representative study: PMID 39433088.
The commonly studied dose of Soy Isoflavones is 40-80mg isoflavones daily (a typical label dose, no cited trial of this supplement alone states a dose). Individual needs vary — start at the lower end of the range and adjust based on how you respond.
The best time to take Soy Isoflavones is with meals. Take it with food. Soy isoflavones (genistein, daidzein, glycitein) are phytoestrogens that act as selective estrogen receptor modulators.
Soy Isoflavones has a safety rating of "moderate". That is a category, not a measure of individual risk, and there are precautions worth knowing. Reported side effects are uncommon and include GI discomfort, bloating. Use caution if any of these apply to you: Hormone-sensitive cancers (consult physician); History of estrogen receptor-positive breast cancer; Soy allergy.
Vitamin D3
Probably helpsHormone-like vitamin that regulates 1,000+ genes — deficiency is widespread and linked to poor immunity, depression, and bone loss.
DHEA
Probably helpsAdrenal hormone precursor that declines with age. In postmenopausal women with normal adrenal function, trials found no effect on sexual symptoms or metabolic markers.
CoQ10
Likely helpsA lipid-soluble antioxidant central to mitochondrial energy production, with the strongest trial support for fertility/IVF outcomes and heart failure.
Collagen
Likely helpsHydrolyzed peptides that rebuild skin elasticity, reduce joint pain, and strengthen bone density — results build over 8-12 weeks.
Explore: Best supplements for Skin, Hair & BeautyBest supplements for Focus, Memory & MoodBest supplements for Vitality & LongevityBest supplements for Women's HealthBest supplements for Body Health
Reviewed by Dr. Baher Al Hakim · Last reviewed May 2026 · evidence from 279 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Tap node to isolate • Pinch to zoom • Tap edge for research