Estradiol (medication)
Estradiol is also available in the U.S. in combination with progestogens for the treatment of menopausal symptoms and as a combined hormonal contraceptive:Estradiol and estradiol esters are also available in custom preparations from compounding pharmacies in the U.S. This includes subcutaneous pellet implants, which are not available in the United States as FDA-approved pharmaceutical drugs. In addition, topical creams that contain estradiol are generally regulated as cosmetics rather than as drugs in the U.S. and hence are also sold over-the-counter and may be purchased without a prescription on the Internet.
Estrone (medication)
Like estradiol, estrone has poor oral bioavailability. It has been said that, taken by mouth in non-micronized form, a dose of 25 mg estrone is approximately equivalent to 2.5 mg conjugated estrogens, 50 µg ethinylestradiol, or 1 mg diethylstilbestrol in terms of estrogenic potency. Due to its weak oral activity, estrone has been used parenterally instead, for instance by intramuscular injection or vaginal administration. The pharmacokinetics of vaginal estrone have been studied.