Estradiol, Estriol and Estrone: What’s the difference?

An excellent Health Journal column in today’s Wall Street Journal, “Sorting Through the Choices for Menopause Hormones,” offers a “brief biology lesson” in the three kinds of estrogen to show that not all Hormone Replacement Therapy products are the same.   Here’s a recap of the article by Melinda Beck:

17-beta Estradiol – this is the predominant hormone that we produce from puberty to menopause and is involved in over 400 functions of the female body. (The depletion of this hormone in our middle years explains why our bodies go through such drastic changes – from thinning hair and dry skin to weaker bones).  A number of FDA-approved patches and gels deliver this type of estrogen.

Estrone - This is the estrogen that is left after menopause, made primarily by body fat. Wyeth’s Premarin, which is the best-selling estrogen in the U.S., is nearly 50 percent estrone.  The article explains that some researchers suspect that estrone may be responsible for the higher risk of breast and endometrial cancer in women who are obese.

Estriol is the weakest estrogen, produced by the placenta during pregnancy and not otherwise present in measurable amounts.

Bio-identical hormones, made by compounding pharmacies, often contain all three estrogens as well as progesterone and are generally made from plant sources.  The FDA recently told compounding pharmacies to stop using estriol, since it isn’t FDA approved.

The article’s author invites readers to share online their experiences using HRT.