Used primarily in hormone replacement therapy (HRT) to alleviate symptoms of menopause such as hot flashes, vaginal dryness, and mood disturbances. It helps restore estrogen levels in postmenopausal women. Also utilized in the treatment of certain hormonal disorders and, less commonly, in some forms of breast cancer in postmenopausal women. Serves as an intermediate in the synthesis of other steroid hormones and pharmaceuticals. Available in various formulations including oral tablets, transdermal patches, and topical creams.