Clostebol caproate (brand name Macrobin-Depot), also known as clostebol hexanoate or chlorotestosterone caproate (JAN), as well as 4-chlorotestosterone 17β-caproate or as 4-chloroandrost-4-en-17β-ol-3-one 17β-caproate, is a synthetic, injected anabolic-androgenic steroid (AAS) and a derivative of testosterone.[1] [2] It is an androgen ester – specifically, the C17β caproate ester of clostebol (4-chlorotestosterone) – and acts as a prodrug of clostebol in the body. Clostebol acetate is administered via intramuscular injection.