The molecule is estran-3-one with a double bond between positions 5 and 10, and bearing both an ethynyl group and a hydroxy group at position 17 (R-configuration). A synthetic steroid hormone drug which acts as an agonist at all five type I steroid hormone receptors, it is used in the prevention of postmenopausal osteoporosis and for treatment of endometriosis. It has a role as a hormone agonist and a bone density conservation agent. It is a 17beta-hydroxy steroid and a terminal acetylenic compound.
(7R,8R,9S,13S,14S,17R)-17-ethynyl-17-hydroxy-7,13-dimethyl-1,2,4,6,7,8,9,11,12,14,15,16-dodecahydrocyclopenta[a]phenanthren-3-one