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Estriol

Ingredient · In our Bi-Est Cream, Bi-Est + Progesterone Cream and Midlife Skin Formula

Estriol (E3)

Estriol is one of the three main estrogens your body makes. It's the weakest of the three, and it's made in large amounts mainly during pregnancy. In midlife care it's used as a gentler partner to estradiol, and on the skin, where small studies suggest it may help with thinning and dryness after menopause.1,3

Abstract pearl glass layers, illustrative ingredient artwork
Estriol

Photos are illustrations, not the medicine. The estriol in these medicines is made in a lab.3

Not FDA-approved in the U.S.

No estriol product is FDA-approved in the United States, so estriol is only available here through compounding pharmacies.2 Estriol has been studied, especially as a vaginal treatment in Europe, but the research on the skin and in combination creams like ours is small.1,5

FDA-approved for this useWell studied, used off-labelEarly evidenceLittle or no human data

The studies below used FDA-approved products or other forms. Our compounded version hasn't been studied in trials, and results may differ.

What it is

Your body makes three main estrogens: estradiol, estrone and estriol. Estriol is the mildest. Outside of pregnancy, your body makes only small amounts of it.

Because it's weaker, estriol is sometimes combined with estradiol in creams often called "Bi-Est", or used on its own on the skin.

Why it's in these products

In Bi-Est Cream and Bi-Est + Progesterone Cream, estriol is paired with estradiol, which does most of the work on hot flashes and night sweats. In Midlife Skin Formula it's applied to the face, where estrogen receptors in the skin are thought to play a part in thickness, firmness and moisture.1

Bi-Est CreamBi-Est + Progesterone CreamMidlife Skin Formula

What the studies in people show

  • Small clinical studySkin: firmer, more hydrated, shallower wrinklesIn a 1996 study, 59 women around menopause applied either 0.3% estriol or 0.01% estradiol cream to their skin for six months. Both groups showed better elasticity, firmness and moisture and shallower wrinkles, and skin samples showed more collagen. No hormone side effects elsewhere in the body were seen. It had no placebo group, which limits how much it can tell us.1
  • Cochrane reviewVaginal estrogen helps drynessA Cochrane review of 30 trials found that estrogen creams, tablets and rings used in the vagina improved vaginal dryness and related symptoms compared with placebo. The evidence was rated low quality.5
  • Expert reportCompounded estriol hasn't been proven equivalentThe National Academies' 2020 review of compounded bioidentical hormones, including estriol, found too little evidence to show they are as safe and effective as FDA-approved hormones.2

What we don't know yet

Whether estriol adds anything meaningful on top of estradiol in a combination cream hasn't been tested in large trials. The skin research is small and old, and we'd like to see bigger placebo-controlled studies. We think you deserve to know that before you decide.

Safety, in plain English

Estriol is an estrogen, so the same cautions that apply to estrogen therapy apply here, including protection of the uterine lining for women who still have a uterus.4 How much reaches your bloodstream from a skin cream can vary.2

A licensed clinician reviews your health history before deciding whether estriol is appropriate for you. Exploring it here never means you'll get a prescription.

Curious about estriol?

Start with a free assessment. A licensed clinician reviews your health history and decides whether treatment is appropriate. No pressure, and no prescription unless it makes sense for you.

See Bi-Est CreamHow care works

Sources

  1. Schmidt JB, Binder M, Demschik G, Bieglmayer C, Reiner A. Treatment of skin aging with topical estrogens. Int J Dermatol. 1996;35(9):669-674. PubMed 8876303
  2. National Academies of Sciences, Engineering, and Medicine. The Clinical Utility of Compounded Bioidentical Hormone Therapy: A Review of Safety, Effectiveness, and Use. Washington, DC: National Academies Press; 2020. NCBI Bookshelf · PubMed 33048485
  3. PubChem, National Center for Biotechnology Information. Estriol (CID 5756). PubChem
  4. The 2022 Hormone Therapy Position Statement of The North American Menopause Society (now The Menopause Society). Menopause. 2022;29(7):767-794. PubMed 35797481
  5. Lethaby A, Ayeleke RO, Roberts H. Local oestrogen for vaginal atrophy in postmenopausal women. Cochrane Database Syst Rev. 2016;(8):CD001500. PubMed 27577677

Sources checked November 8, 2026. This page is general education, not medical advice, and it doesn't mean any treatment is right for you. Photos: Unsplash (Herbert Goetsch, David Becker, Jing Bo Wang).