It is an injectable formulation of the anabolic steroid Testosterone Propionate . This compound is a synthetic version of testosterone that acts quickly due to its short half-life, requiring frequent injections (usually every two or three days). It is primarily used in testosterone replacement therapy (TRT) in men with low hormone levels (hypogonadism) and, historically, has also been used to treat breast cancer in women. In the context of non-medical use, it is sought after for its androgenic and anabolic effects (increased muscle mass and strength), and is classified as a controlled substance in many countries due to its potential for abuse.