All Estrogens Are Not Created Equal

There is a lot of confusion in the medical and non-medical communities regarding estrogens. Many today think there is only one estrogen. Many today think bioidentical estrogens and synthetic estrogens are identical in structure and function. Many today think estrogen production stops after menopause or after a total hysterectomy. However, this couldn’t be further from the truth.

The body never stops producing estrogens. The body, in fact, produces 3 types of estrogens: estradiol, estrone, and estriol. These are the natural estrogens native to the body and the foundation of bioidentical hormone replacement of estrogen.

A woman’s body produces estrogens in various places. Most people knows that ovaries produce estrogens. But did you know that the adrenal glands and fat cells produce estrogens, too? Think about that for a minute. This explains why women of all ages continue produce estrogen. Our adrenal glands don’t disappear at menopause. And fat cells certainly don’t. So how do we know if a woman needs estrogen?

Let’s look more closely at the 3 main estrogens produced in the body.

• estradiol
• estrone
• estriol

Estriol is a good place to start. Estriol is the weakest of all Estrogens. A woman’s placenta produces very large amounts of estriol during pregnancy. However, estriol is not confined to pregnancy. The liver produces small amounts, too. Estriol primarily affects a woman’s hair, nails, skin, and her vaginal lining. Studies also suggest estriol has potential in breast cancer prevention because estriol binds to specific receptors (beta-receptors) in the breast that inhibit breast cell growth. All other estrogens would be expected to increase breast cell growth (which can lead to cancer) through activity with alpha-receptors.

Estrone is the second most potent estrogen. Estrone is predominately produced in fat cells after menopause. Overweight women have high circulating estrone levels. Unfortunately, 63% of American women are overweight or obese, so many women have high estrone levels. Estrone levels rise even more after menopause, and estrone has been implicated in breast tumors in animal studies. (Scientists say this because estrone has a 5:1 affinity for alpha breast receptors, but that’s pretty technical.) Just remember that alpha-receptors increase breast cell growth. You could say estrone encourages breast cell growth, and that can lead to uncontrolled breast cell growth. We call that breast cancer.

Estradiol is the most potent estrogen. Estradiol is produced predominately from the ovaries. This means a woman will have less estriadiol after menopause because her ovaries are producing less. Estradiol is the main stimulus for growth of the lining of the uterus in the first 2 weeks of the monthly cycle, and it helps in triggering ovulation. Like estrone, estradiol has been implicated in breast tumors. It has a 3:1 affinity for alpha-receptors in the breasts, which promote breast cell growth and can lead to cancer.

That’s a lot of information for one blog post, I know. But remember the overall point. Bioidentical hormone therapy is much more than the use of bioidentical estrogen. It is about which estrogens your body needs to maximize efficacy, reduce side effects, and prevent disease.

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