Sustanon 250 is an oil-based injectable Testosterone blend. Sustanon developed by the international drug firm Organon. The substance 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 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 stayes active in the body for about two and three weeks (respectively). This is a big improvement of Sustanon from standard Testosterones such as cypionate or enanthate, which provide a much shorter duration of activity, and a more variable blood level.