Sustanon is a trade name owned by Organon Pharmaceuticals for oil-based injectable blends of esterified testosterone compounds.
Sustanon 250 is a blend of four esterified testosterone compounds:
- 30 mg testosterone propionate
- 60 mg testosterone phenylpropionate
- 60 mg testosterone isocaproate
- 100 mg testosterone decanoate
Sustanon 100 was similar, though with three esters. This smaller dose was usually for pediatric use.
- 20 mg testosterone propionate
- 40 mg testosterone phenylpropionate
- 40 mg testosterone isocaproate
Sustanon 100 has not been produced since 2009.
The numbers in the names refer to the fact that the content of testosterone compounds in each blend are 250 and 100 mg/ml, respectively.
The different testosterone esters provide for different half-lives. Esterization of the testosterone molecules provides for a sustained (but non-linear) release of testosterone hormone from the injection depot into the blood plasma.
While the intention of the mixed testosterone esters in Sustanon is to provide more stable serum testosterone levels, a single long-ester testosterone, such as testosterone cypionate or testosterone enanthate, may actually provide more stable serum testosterone levels.
Sustanon is the preferred method of testosterone replacement in the UK as detailed in the British National Formulary. There was a brief shortage of Sustanon 250 during late 2011, due to licensing problems and a further shortage in mid-2012 due to manufacturing problems.
This form of testosterone is a popular choice of anabolic steroid among bodybuilders and athletes.