In the Steroid Hormone Cascade a woman’s body makes 3 forms of estrogen.
E1 or Estrone: Main estrogen your body produces post-menopausally. High levels may increase your risk for developing breast & uterine cancer. It is derived from estradiol. In your later years reasons for elevated estrone include being overweight, high alcohol consumption or taking too much estradiol. Note the arrows, too much estradiol can roll to estrone.
E2 or Estradiol: Strongest form of estrogen. It is 12 times stronger than Estrone and 80 times
stronger than Estriol. It is the main estrogen your body produces before menopause. Made in the ovaries, this is the estrogen you lose at menopause. However most women will make 60% of the estrogen after menopause that they made before menopause.
E3 or Estriol: Estriol has a much lesser stimulatory effect on the breast and uterine lining.
Estriol does not promote breast cancer and can actually protect against breast cancer. The
main estrogen of pregnancy with emerging clinical benefits. Estriol can modulate 1) the
immune system 2) reduce inflammation 3) prevent neuro-degenerative change. Note the
arrows …. elevated amounts do NOT roll back to make estrone or estradiol.
So if your prescription read Bi-est 1mg in an 80:20 split it means 0.2mg
estradiol & 0.8mg estriol.