Testosterone cypionate is a slow-acting injectable ester of the primary male androgen testosterone. Testosterone also the principle anabolic hormone in men, and is the basis of comparison by which all other anabolic/androgenic steroids are judged. As with all testosterone injectables, testosterone cypionate is highly favored by athletes for its ability to promote strong increases in muscle mass and strength. It is interesting to note that while a large number of other steroidal compounds have been made available since testosterone injectables, they are still considered to be the dominant bulking agents among bodybuilders. There is little argument that these are among the most powerful mass drugs available, testosterone cypionate included.