Progesterone has two categories of functions, one function is as a pro-hormone that may be converted into other hormones such as cortisol, and two it has metabolic activity in and of itself such as helping reduce excessive amounts of insulin. Progesterone is a building block for many of your body's most critical hormones. Your body can quickly and easily convert it into a hormone it needs when it needs it at that moment -- a true adaptogenic response. Progesterone is not a drug; it’s a hormone that occurs in your body naturally. Natural progesterone is vital in offsetting estrogen dominance, one of the most common conditions in perimenopause, which is the underlying cause of a host of symptoms. Progesterone is naturally secreted by the ovary in the second two weeks of the menstrual cycle in ovulating women. Progesterone is are also ingested by women in birth control pills, menopausal hormone replacement therapy, or just sometimes to induce a menstrual period or regulate abnormal bleeding problems if menses are skipping or bleeding is irregular or prolonged. Progesterone has been used also as therapy for PMS syndrome and for women with infertility or frequent pregnancy loss. Progesterone is a drug in the strict legal definition, but is better understood as a bio-identical hormone, not as a synthetic progestin such as medroxy-progesterone which has the brand name of Provera. Progestins are synthetic hormones; they are NOT the same as progesterone!