Cyproterone acetate is a steroid ester resulting from the formal condensation of the carboxy group of acetic acid with the 17-hydroxy group of cyproterone. It is an antiandrogenic drug which has recently been recognized to promote the occurrence and growth of intracranial meningiomas. It has a role as an androgen antagonist, a progestin and a geroprotector. It is a 20-oxo steroid, a 3-oxo-Delta(4) steroid, a chlorinated steroid, a steroid ester and an acetate ester. It is functionally related to a cyproterone.