Vinyltestosterone

Vinyltestosterone, or 17α-vinyltestosterone, also known as 17α-vinylandrost-4-en-17β-ol-3-one, as well as 17α-hydroxypregna-4,20-dien-3-one, is a synthetic, steroidal androgenic-anabolic steroid (AAS) that was never marketed. It is a relatively weak AAS. In one study, vinyltestosterone showed approximately one-third and one-fifth of the respective androgenic and anabolic activity of other AAS such as nandrolone, methyltestosterone, and ethyltestosterone in castrated male rats, whereas ethisterone showed almost no androgenic and anabolic activity (only 1/20th the anabolic potency of vinyltestosterone). Additionally, in women with metastatic breast cancer, vinyltestosterone was found to be ineffective in treating the disease (unlike other AAS such as testosterone propionate or fluoxymesterone) and produced little or no virilization in the women at a dosage of 100 mg intramuscularly three times per week. Aside from vinyltestosterone itself, two 19-nortestosterone derivatives of vinyltestosterone, norvinisterone (17α-vinyl-19-nortestosterone) and norgesterone (17α-vinyl-δ⁵⁽¹⁰⁾-19-nortestosterone), have, in contrast, been marketed. They are used as progestins for female hormonal contraception, rather than as AAS.