The body may absorb wild yam extract through the skin, which may in turn have some effect on menopausal symptoms, yet research on both oral and topical applications of wild yam extract demonstrate no change in progesterone levels in the body. Progesterone binds with progesterone receptor sites in the brain and causes a calming effect on the central nervous system. In excessive amounts, progesterone may have a relaxing effect on the brain, and may cause drowsiness. In a very small group of women who are extremely sensitive, progesterone of any kind may aggravate hormonal headaches or PMS symptoms. There are no long-term adverse effects noted for supplemental progesterone in amounts that replicate physiological levels of progesterone in the body.
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.