What is testosterone cypionate?

Testosterone cypionate consists of testosterone attached to a cypionate ester, a chemical modification that extends the hormone's duration in the bloodstream. Administered by intramuscular injection, it is one of the most widely prescribed forms of testosterone in US clinical settings, particularly in hormone therapy practices.

The drug has a half-life of approximately 8 days, meaning half the injected dose is eliminated from the body over that period. Most TRT clinics prescribe injections every 7 to 14 days, with weekly dosing most common. This schedule allows testosterone levels to remain relatively stable between shots, avoiding the sharper peaks and troughs that occur with shorter-acting esters.

Testosterone cypionate is oil-based and typically supplied in single-dose or multi-dose vials. Patients self-inject subcutaneously or receive intramuscular injections at the clinic. Common injection sites include the gluteal muscle, deltoid, or anterior thigh. Like all testosterone therapies, it requires regular blood work to monitor levels and adjust dosing as needed. It is a controlled substance under the Anabolic Steroid Control Act and requires a prescription.