Rosterolone () (developmental code name SH-434), also known as 17ñ-propylmesterolone or 1ñ-methyl-17ñ-propyl-5ñ-androstan-17ò-ol-3-one, is a steroidal antiandrogen which was first described in 1984 and was developed for topical administration but was never marketed. It has shown some efficacy in the treatment of acne, and lacks systemic effects with either topical or systemic administration. Rosterolone is a derivative of mesterolone, which, in contrast, is an androgen and anabolic steroid.