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Estriol is a naturally occurring estrogen that Bayview compounds to a prescriber's order.
Estriol is a naturally occurring estrogen and one of the three predominant female sex hormones, alongside estradiol and estrone.[1] It is primarily synthesized in the placenta during pregnancy and is a far less potent estrogen than estradiol; with little circulating in nonpregnant women, it serves as a minor female sex hormone.[1]
Estriol is not available in any FDA-approved drug product, but the existence of a USP-NF monograph for estriol allows it to be compounded.[2] It is used in compounded preparations such as Bi-est (estradiol and estriol) and Tri-est (estradiol, estriol, and estrone), and as a compounded vaginal preparation.[2]
Some studies have suggested that estriol may pose a lower risk of promoting endometrial cancer, but these conclusions are debated, and a population-based study found that oral estriol increases the relative risk of endometrial cancer.[3] A National Academies committee was unable to identify studies of compounded estriol's effectiveness for vasomotor symptoms or vaginal atrophy, or studies of its safety with respect to breast cancer.[3]
Bayview Pharmacy compounds estriol preparations on a prescriber's order.
Compounded at Bayview
Patient guides for the preparations we make most often. Each one is compounded to order and requires a prescription.
For prescribers
Every preparation in our formulary that contains this ingredient. Strength, base and dose form are set by the prescription.
Providers may use low-dose vaginal estriol as part of care for the genitourinary syndrome of menopause, vaginal dryness, irritation, and discomfort with intercourse, when they determine it is appropriate. A valid prescription is required.
No. Low-dose vaginal estriol acts mainly on the local tissue and is absorbed into the rest of the body only in small amounts. Major societies distinguish low-dose vaginal estrogen from systemic estrogen therapy, and in 2025 the FDA removed the boxed warning from low-dose vaginal estrogen. Your provider decides what is right for you.
Compounded vaginal estriol starts at $70 for 20 g, and the price varies with the form, strength, and size. Compounded preparations are cash-priced and are generally eligible for HSA and FSA cards. Where an FDA-approved vaginal estrogen product fits your prescriber's order, that is what we dispense, and it may be covered by your insurance. Call us at 401-284-4505 with the preparation and quantity your prescriber ordered and we will quote it before we make it.
No. They are two different estrogens the body makes. Estradiol (E2) is the most potent and is the main estrogen before menopause; estriol (E3) is the weakest of the three natural estrogens. That difference in potency is usually why a prescriber picks one over the other for local vaginal use. They are not interchangeable, and estradiol has FDA-approved low-dose vaginal products while estriol does not — estriol is available only as a compounded preparation. Which one suits you is your prescriber's decision.
No. There is no FDA-approved estriol product in the United States, which is why vaginal estriol is available only through a compounding pharmacy and only against a valid prescription. Compounded preparations are not reviewed by the FDA for safety or effectiveness. FDA-approved low-dose vaginal estrogen products do exist using estradiol, and where one of those fits your prescriber's order, that is what a pharmacy dispenses.
Other salt forms of this molecule, and ingredients commonly compounded alongside it.
This page describes an active pharmaceutical ingredient, not a finished drug product. Bayview Pharmacy compounds preparations containing it only on a prescriber's order for an individual patient.
Compounded preparations are not FDA-approved, and the FDA has not evaluated them for safety, effectiveness, or manufacturing quality. Nothing on this page is a claim that any preparation is effective for any condition.
A valid prescription is required. Availability depends on Bayview's licensure in your state. This page is general information, not medical advice — discuss your situation with a licensed healthcare provider.
Our pharmacists work with prescribers to build preparations around a patient's dose, form and tolerances. Ask us what is possible with this ingredient.
