Compound or practice · Supplement
Soy Isoflavones
Phytoestrogens with real, modest evidence for menopausal hot flashes — and no, they don't feminize men.
- Overall grade
- Grade B
- Last revised
- 2
- graded outcomes
- 0
- references listed
A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.
2 at grade B · 1 at grade D — 3 graded rows
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Menopausal hot flashesEvidence grade B
Better in equol producers
Smallmixed
- Male testosteroneEvidence grade D
No meaningful effect
Trivialhigh
Conditions
How the entry reads its effect on diagnosed conditions: the direction first, then the grade. Never a substitute for the person who treats you.
- Menopause symptoms May improveEvidence grade BHot flashesGrade B
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
- Thin evidence: Male testosterone (grade D).
- Studies disagree: Menopausal hot flashes (mixed agreement).
The evidence in words
What it is
Soy isoflavones (genistein, daidzein) are dietary phytoestrogens used for menopausal symptoms and bone.
How it works
They bind estrogen receptors (preferentially ER-beta) with weak estrogen-like activity, modulating menopausal symptoms.
What the evidence shows
Meta-analyses support a modest reduction in hot-flash frequency/severity, with better response in 'equol producers.' Bone and cardiovascular signals are smaller. Extensive data show typical intakes do not lower testosterone or feminize men, and do not increase breast-cancer risk (may modestly lower it).
How to use it
40–80 mg isoflavones/day from soy foods or supplements; give it several weeks.
Safety & interactions
Safe at dietary/supplemental doses; discuss with an oncologist if you have hormone-sensitive cancer.
Bottom line
A legitimate, modest option for hot flashes — and the 'soy lowers testosterone' fear is not supported. 40–80 mg/day.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Standard
- 40–80 mg isoflavones/day.
Related reading
Entries that share this one's tags or conditions.
- Red CloverAnother isoflavone source for menopause with weaker, more inconsistent data than soy.Evidence grade C
- Red Clover for Menopausal hot flashesEvidence grade C — InconsistentEvidence grade C
- Red Clover for Menopause symptomsEvidence grade C — InconsistentEvidence grade C
- Red Clover: dosage and how to take itStandardized isoflavone extract daily.Evidence grade C
Sources
This entry lists no references of its own.
Last revised . A grade is this entry's reading of the evidence, not medical advice.