Progesterone(CAS No.57-83-0) (P4) 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. Progesterone has a variety of important functions in the body. It is also a crucial metabolic intermediate in the production of other endogenous steroids, including the sex hormones and the corticosteroids, and plays an important role in brain function as a neurosteroid. In addition to its role as a natural hormone, progesterone is used as a medication, for instance in menopausal hormone therapy; for information on progesterone as a medication, see the progesterone (medication) article.

1.Progesterone also known as P4 is a C-21 steroid homone involved in the female menstrual cycle, pregnancy(support gestation) and embryogenesis of humans and other species.

2.Progesterone belongs to a class of hormones called progestogens, that is major naturally occurring humanprogestogen.