Mesterolone cipionate is a synthetic anabolicâÂÂandrogenic steroid and an androgen ester â specifically, the C17ò cypionate ester of mesterolone â which was never marketed. It is administered via intramuscular injection once every two weeks and acts as a long-acting prodrug of mesterolone. The drug was studied in the treatment of depression in men along with mesterolone in the mid-1970s but was never introduced for medical use.