Cloxotestosterone acetate (INN; brand name Caprosem), also known as testosterone 17β-chloral hemiacetal O-acetate, is a synthetic, injected anabolic–androgenic steroid (AAS) and an androgen ether and ester – specifically, the O-acetate ester of cloxotestosterone, the 17β-trichloro hemiacetal ether of testosterone. It is administered via intramuscular injection as a 100 mg, 2 mL aqueous suspension and lasts 4 to 6 weeks with a single administration. The drug was first marketed in the early 1960s.