Sustanon 250 is an oil-based injectable Testosterone blend. Sustanon 250 developed by the international drug firm Organon. Sustanon 250 typically contains four different Testosterone esters: Testosterone propionate (30 mg); Testosterone phenylpropionate (60 mg); Testosterone isocaproate (60mg); and Testosterone decanoate (100 mg), although a lower dosed version is also produced. An intelligently "engineered" Testosterone, Sustanon 250 is designed to provide a fast yet extended release of Testosterone. The propionate and phenylpropionate esters are quickly utilized, releasing into circulation within the first four days. The remaining esters are much slower to release. Sustanon 250 stayes active in the body for about two and three weeks (respectively). This is a big improvement of Sustanon 250 from standard Testosterones such as cypionate or enanthate, which provide a much shorter duration of activity, and a more variable blood level. As with all Testosterone products, Sustanon 250 is a strong anabolic with pronounced androgenic activity. Sustanon 250 is most commonly used as a bulking drug, providing exceptional gains in strength and muscle mass. Although it does convert to estrogen, as is the nature of Testosterone, Sustanon 250 injectable is noted as being slightly more tolerable than cypionate or enanthate.