Progesterone is secreted by the ovaries and reduces symptoms of premature menstrual syndrome. It protects against uterine and breast cancers, osteoporosis, fibrocystic disease and ovarian cysts. It dramatically decreases menopausal symptoms. Most U.S. physicians prescribe synthetic progestins which cause such side effects as bloating, headaches, fatigue and weight gain, and most recently are associated with increasing the risk of cancer. Bio-identical progesterone must be prescribed in place of the synthetic progestin to avoid the side effects and protect against cancer. Progesterone is very beneficial in treating premenstrual symptoms (PMS) such as mood swings and migraine headaches.