Testosterone Propionate is the shortest-estered testosterone steroid. It’s an injectable compound with a slower rate of release than un-esterified Testosterone, but a faster rate of release than all the rest of esterified are some advantages and disadvantages to the short acting ester. The major disadvantage is that users have to inject Testosterone Propionate at minimum every other day throughout the cycle to get proper results. The advantages, however, are easier control and prevention of potential side effects. Also because there is less ester per vial, there is more actual testosterone per injection, which produces better results. The Propionate ester expands Testosterone’s half-life to about 4 and a half days.
Testosterone Propionate also converts to both Estrogen (through Aromatization) and Dihydrotestosterone (through 5a-reduction). Most of the side effects people experience with testosterone use is actually from it’s conversion to these two substrates. Thus, hair loss , water retention, acne, and other side effects are possible with use of this drug. Conversion to these hormones is also responsible for some of testosterone’s ability to build muscle; therefore when many side effects are avoided with the use of ancillary compounds, some of the muscle building properties are also stunted.