Progesterone Hormone Description DescriptionProgesterone is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens, and is the major progestogen in the body. buy Progesterone Cream online Formula: C21H30O2 Molar mass: 314.46 g/mol Melting point: 126 Biological half-life: OMP: 16–18 hours; IM: 22–26 hours; SC: 13–18 hours Bioavailability: OMP: <10% Log P: 4.04