Testosterone acetate propionate, or testosterone 3β-acetate 17β-propanoate, also known as 4-androstenediol acetate propionate, as well as androst-4-ene-3β,17β-diol 3β-acetate 17β-propanoate, is a synthetic anabolic-androgenic steroid and an androgen ester which was never marketed.[1] It is the 3β-acetate, 17β-propionate (propanoate) diester of testosterone (androst-4-en-17β-ol-3-one), or, more accurately, of 4-androstenediol (androst-4-ene-3β,17β-diol).