Testosterone benzoate, or testosterone 17β-benzoate, also known as androst-4-en-17β-ol-3-one 17β-benzoate, is a synthetic, injected anabolic–androgenic steroid (AAS) and an androgen ester – specifically, the benzoate C17β ester of testosterone – 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.