Background: Nandrolone decanoate, is an androgen and anabolic steroid (AAS) medication sold under the brand name Deca-Durabolin. It is used largely in the treatment of anemias and wasting syndromes, as well as osteoporosis in menopausal women. It is administrated by injection into muscle or fat once every one to four weeks. Compared to testosterone propionate, nandrolone decanoate is considered to have strong anabolic effects but weak androgenic effects. In particular, nandrolone esters are thought to have the highest ratio of anabolic to androgenic effects of any AAS. The low androgenicity of nandrolone decanoate is thought to be due to the fact that nandrolone is inactivated by 5α-reductase via transformation into the low-affinity androgen receptor (AR) ligand 5α-dihydronandrolone. This is thought to result in a lower incidence and magnitude of side effects. Nandrolone decanoate is a prodrug of nandrolone. it is an androgen and anabolic steroid with enhanced anabolic effects and reduced androgenic effects unlike testosterone. The side effects of nandrolone decanoate are related to dose, individual sensitivity and interval of treatment. The most common side effect of nandrolone decanoate is virilization (masculinization) in women.