Progesterone is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species.
Progesterone also known as P4 (pregn-4-ene-3,20-dione) is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. Progesterone belongs to a class of hormones called progestogens, and is the major naturally occurring human progestogen.
The route of administration impacts the effect of the drug. Given orally, progesterone has a wide person-to-person variability in absorption andbioavailability while synthetic progestins are rapidly absorbed with a longer half-life than progesterone and maintain stable levels in the blood. Progesterone does not dissolve in water and is poorly absorbed when taken orally unless micronized in oil. Products are often sold as capsules containing micronised progesterone in oil. Progesterone can also be administered through vaginal or rectal suppositories or pessaries, transdermally through a gel or cream, or via injection (though the latter has a short half-life requiring daily administration). Transdermal "natural progesterone" products made with Progesterone USP do not require a prescription. Some of these products also contain "wild yam extract" derived from Dioscorea villosa, but there is no evidence that the human body can convert its active ingredient (diosgenin, the plant steroid that is chemically converted to produce progesterone industrially) into progesterone.