Coumesterol

PhytochemicalIsoflavonoid

What is it

Coumesterol is a coumestan-class phytoestrogen found in alfalfa, clover sprouts, soybeans, and other legumes. It is structurally distinct from isoflavones but binds estrogen receptors with notable affinity.

How it works

Coumesterol binds estrogen receptors (with preference for ER-beta) and exerts mixed agonist/antagonist effects depending on tissue and endogenous estrogen levels. Animal studies have explored effects on reproductive tissues, bone, and metabolism. Human evidence is limited and largely confined to dietary intake studies.

Dosage

No standardized supplement dose for isolated coumesterol. Dietary intake from alfalfa or clover sprouts is in the milligram range; supplement levels vary.

When and how to take it

No formal timing guidance.

1 commercial form

Compare the main delivery options and what they’re best suited for.

Plant extract (alfalfa or clover)

Most common source of coumesterol in supplements.

Absorbed and circulated as parent compound and metabolites

Safety

At dietary intake levels, generally well tolerated. Concentrated phytoestrogen supplements may produce hormonal effects in sensitive individuals. Long-term safety of isolated coumesterol is not well characterized.

Who should be cautious

Avoid concentrated supplemental use in pregnancy, breastfeeding, hormone-sensitive cancers (breast, ovarian, uterine), and in children.

Interactions

Possible additive effects with hormone therapy or selective estrogen receptor modulators. Coordinate with a clinician.

Food sources

Alfalfa sprouts

Amount
rich in coumesterol
%DV
—

Clover sprouts

Amount
rich in coumesterol
%DV
—

Split peas

Amount
modest amounts
%DV
—

Frequently asked questions

Is coumesterol a phytoestrogen?⌄

Yes. It binds estrogen receptors and can have mild estrogenic activity in some tissues.

Should I avoid foods with coumesterol?⌄

Dietary intake from sprouts and legumes is generally safe. Concentrated supplements warrant more caution, especially with hormone-sensitive conditions.

References

Coumesterol on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Coumesterol (PubMed search) — PubMed link

Track Coumesterol with Pilora

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.