Oxymetholone is a very popular mass gaining anabolic steroid and i highly effective in doin so by greatly improving protein synthesis. Like other AAS, Oxymetholone is an agonist of the androgen receptor and therefor shows a high ratio of anabolic to androgenic activity. As a DHT derivative, Oxymetholone is not a substrate for aromatase and hence cannot be aromatized into estrogenic metabolites. However, uniquely among DHT derivatives, Oxymetholone is nonetheless associated with relatively high esirogenicity and is known to have the potential to produce estrogenic side effects. Pharmaqo have synthesized an injectable version which has an active life of 16 hours and is very popular amongst strength athletes.