Sustanon 250 is an oil-based injectable testosterone blend that contains four different testosterone esters: testosterone propionate (30 mg); testosterone phenylpropionate (60 mg); testosterone isocaproate (60 mg); and testosterone decanoate (100 mg). Sustanon® is designed to provide a fast yet extended release of testosterone, usually requiring injections once every 3 to 4 weeks in a clinical setting.
This is an improvement from standard testosterones such as cypionate or enanthate, which provide a shorter duration of activity. As with all testosterone products, Sustanon 250 is a very strong anabolic drug with pronounced androgenic activity. It is most commonly used in bulking cycles, providing exceptional gains in strength and muscle mass. A shorter-acting version of Sustanon, called Sustanon 100, is also made in certain areas (see:Sustanon 100).