Estriol (E3)

What is Estriol (E3)?

Estrogen is the main female sex hormone, and estriol (E3) is a form of estrogen. In contrast to estrone (E1) and estradiol (E2), estriol (E3) is secreted mainly by the placenta rather than the ovaries and is the dominant estrogen during pregnancy. Levels of estriol in women who are not pregnant are almost undetectable.

Both women and men have estrogen, including estriol, in their bodies. However, men produce only very small amounts of estriol.

Of the three major estrogens, estriol forms the weakest bonds with estrogen receptors. It is a short-acting estrogen. These characteristics are useful because some of the potential negative effects of estrogen depend on long-term interaction. Estriol has been found to provide some of the protection without the risks associated with stronger estrogens.

E3 is available only as a compounded bioidentical hormone medication. Bioidentical hormones have the exact chemical and molecular structure and function as hormones made in the human body. Bioidentical estriol is derived from plant sources.

Who May Benefit From Estriol Replacement?

Estriol supplementation may be a beneficial treatment for:
Menopausal women

Some of the symptoms that may respond to estriol treatment include hot flashes, night sweats, insomnia, skin issues, vaginal atrophy, and frequent urinary tract infections.

Elderly men and women with osteoporosis

Estriol has been shown to improve bone mineral density by inhibiting bone absorption. It may also improve endothelial function. Because it doesn’t impact other parts of the body in the same way as the stronger estrogens, it may be an option for use in bioidentical hormone replacement therapy (BHRT) in elderly patients.

Men and women with autoimmune disorders

Estriol can be used to help in the treatment of patients with Th1-mediated autoimmune diseases, including multiple sclerosis and rheumatoid arthritis. At levels similar to those found in pregnant women, E3 has been seen to regulate the immune response and improve symptoms.

How Belmar Can Help

If you’re a clinician interested in prescribing compound medications to your patients, contact us for information on how to get started and to access all of our clinical resources. If you are new to compounding, you may find our page on How to Write a Compounding Prescription helpful. You can also visit our Treatment Options page to find a formulary and learn more about all the medication solutions available from Belmar.