 Prostate cancer is one of the most frequently diagnosed noncutaneous cancers among men in the US and is the second most common cause of cancer deaths. Patients with advanced prostate cancer undergo androgen deprivation therapy ADT, by either LHRH agonists, LHRH antagonists, DES and other nonselective estrogens, or by bilateral orchiectomy. ADT by LHRH agonists, LHRH antagonists, or bilateral orchiectomy not only reduces testosterone, but also substantially lowers estrogen levels as estrogen is derived from the aromatization of testosterone. ADT-induced estrogen deficiency causes significant side effects which include hot flushes, gynecomastia, bone loss, decreases in bone quality and strength, osteoporosis and life-threatening fractures, adverse lipid changes, increase in body fat composition, and higher cardiovascular disease and myocardial infarction, and depression and other mood changes. 