Whats the difference between synthetic and natural estrogen?
The body naturally produces three main forms of estrogen: estrone (E1), estradiol (E2), and estriol (E3). Estrone is converted from estradiol in the liver. Synthesized in the ovaries and metabolized in the liver, estradiol is the most physiologically active form of estrogen. When taken orally, estradiol is converted into estrone in the small intestine. Estriol is the shortest-acting estrogen and has a weaker effect than estradiol and estrone. Estriol remains intact when supplemented orally, i.e. estriol is not converted into estrone, as is true with estradiol supplementation. Because estriol competes with estrone for receptor uptake when given in large or repeated doses, it may have an anti-estrogenic effect in selective tissues like the breasts or uterus. Estriol doses must be increased up to three times the dose of estradiol to achieve similar effects (e.g. reducing hot flashes and vaginal dryness in menopausal women). In Europe and China, estriol is the preferred form of estrogen fo
