Testosterone benzoate, or testosterone 17ò-benzoate, also known as androst-4-en-17ò-ol-3-one 17ò-benzoate, is a synthetic, injected anabolicâÂÂandrogenic steroid (AAS) and an androgen ester â specifically, the benzoate C17ò ester of testosterone â which was never marketed. It is a prodrug of testosterone and, when administered via intramuscular injection, is associated with a long-lasting depot effect and extended duration of action. The drug was first described in 1936 and was the first androgen ester and ester of testosterone to be synthesized.