Testosterone is the main male sex hormone (androgen) in the body, and as such still the best possible muscle mass builder available. It has a high risk of side effects because it easily converts to a more androgenic form (DHT) in androgen responsive tissues and it also forms estrogen quite easily. But at the same time, these characteristics also ensure the extremely anabolic effect. On the one hand, estrogens increase growth hormone release, utilize glucose, improve immunity and upgrade the androgen receptor, while on the other hand, a testosterone/DHT combination is extremely potent at activating the androgen receptor and thereby significantly increasing the muscle strength and muscle mass increase. Although the result is not always the most visually appealing,
Sustanon 250 is a unique blend of 4 different testosterone esters. The purpose of attaching an ester to a steroid is to cause it to become more lipophilic (fat soluble) so that when the steroid is injected intramuscularly, it can reside longer in the adipose tissue and is gradually released into the blood stream. The longer an ester, the more lipophilic it is. Sustanon 250 contains 1 short, 1 long and 2 medium esters that are all released after a certain time, which ensures an immediate fast release, but also a long-lasting effect. This seems to be a good feature, and probably better for people on hormone replacement therapy, but it seems much less interesting for the steroid user.