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Moderate evidenceWomen's health

S-Equol

The active soy metabolite that only about a third of people produce themselves. Supplementing it reduces hot flashes modestly, with the clearest signal in women who cannot make their own.

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What the science says

  • Hot flash frequency Moderate evidence

    A systematic review and meta-analysis of randomized trials concluded that equol supplementation reduces hot flashes in postmenopausal women. The pooled effect is modest and rests on a small number of trials.

  • Benefit concentrated in equol non-producers Limited evidence

    A pilot study comparing S-equol with conventional soy isoflavones found the effect on hot flash frequency was most apparent in women who do not produce equol from soy themselves. This is a plausible but under-tested hypothesis.

Dosage & safety

Studied doseTrials have used 10-30 mg of S-equol daily, most often 10 mg once or twice a day for 8-12 weeks.
SafetyWell tolerated in trials of up to a year, with mild digestive complaints most common. Because it is an estrogen receptor beta agonist, women with hormone-sensitive breast cancer or on tamoxifen should consult their oncologist before use. Not for pregnancy or breastfeeding.

How to take it

TimingTiming does not matter; trials used it once or twice daily.
With food?With or without food.
Worth knowingRoughly half to two-thirds of people cannot produce equol from soy themselves, and those are the people a supplement is actually for.

Interactions

With medications

  • tamoxifen and aromatase inhibitors

    S-equol is an estrogen receptor beta agonist and its effect alongside endocrine therapy is unstudied. do not use without your oncologist's agreement

With other supplements

  • soy isoflavone supplements

    Overlapping estrogen-receptor activity, with no reason to take both. pick one rather than stacking them

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does S-equol help hot flashes?

Yes, modestly: a meta-analysis of randomized trials found equol supplementation reduces hot flashes in postmenopausal women, a moderate-grade finding based on a small number of trials.

Who benefits most from S-equol?

S-equol is aimed at people who cannot make equol from soy themselves, roughly half to two-thirds of people. A pilot study found the hot flash benefit was most apparent in these non-producers, but that idea is under-tested.

How much S-equol should I take?

Trials used 10-30 mg of S-equol daily, most often 10 mg once or twice a day for 8-12 weeks, with or without food.

Is S-equol safe after breast cancer?

S-equol is an estrogen receptor beta agonist, so women with hormone-sensitive breast cancer or on tamoxifen should not use it without their oncologist's agreement. Otherwise it was well tolerated in trials of up to a year, with mild digestive complaints most common.

Scientific references

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