Cloxotestosterone acetate (; brand name Caprosem), also known as testosterone 17ò-chloral hemiacetal O-acetate, is a synthetic, injected anabolicâÂÂandrogenic steroid (AAS) and an androgen ether and ester â specifically, the O-acetate ester of cloxotestosterone, the 17ò-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.