Estriol: How It Works, What It's Studied For & Safety
Estriol is a weaker endogenous estrogen produced primarily during pregnancy; used in compounded bio-identical hormone preparations, especially vaginal applications. Clinicians consider it for genitourinary syndrome of menopause (off-label in the US; widely used in Europe). Not FDA-approved; dispensed by Wells Pharmacy Network only after a clinician evaluation.
Also known as: E3
How does Estriol work?
Estriol is a short-acting estrogen that binds estrogen receptors with lower affinity than estradiol. Local vaginal application is studied for genitourinary syndrome of menopause with reduced systemic exposure.
What is Estriol studied for?
- Genitourinary syndrome of menopause (off-label in the US; widely used in Europe)
- Compounded bi-est (E2 + E3) and tri-est (E1 + E2 + E3) hormone-replacement preparations
How is Estriol taken?
Compounded as vaginal creams, suppositories, and oral preparations. Not currently FDA-approved as a stand-alone finished drug in the US.
Is Estriol FDA-approved? Is it safe?
Not FDA-approved for the prevention, treatment, or cure of any condition. Used inside research-informed, clinician-directed protocols only. The FDA has previously cautioned that compounded bio-identical hormone replacement is not a substitute for FDA-approved alternatives. Compounded prescription-only preparations are dispensed by Wells Pharmacy Network. Eligibility is decided by a licensed clinician based on intake and labs, not by checkout. Compounded products on this site are not FDA-approved and are not generic equivalents of any branded medication.
In the Regen Therapy catalog
This compound does not currently appear in an active Regen Therapy protocol. Browse the full catalog for adjacent options.
What does the research say about Estriol?
Decades of European clinical experience; US literature is more limited.
Citations & further reading
Considering Estriol as part of a protocol?
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