Testosterone Propionate is one of the many esterified variants of Testosterone available. It is an injectable compound with a slower rate of release than un-esterified Testosterone, but a faster rate of release than all other esterified forms commonly available. This is due to the larger Propionate ester attached to the Testosterone molecule. This augments the release rate and half-life of Testosterone to that of a faster release than other common esterified variants, such as Testosterone Enanthate or Testosterone Propionate. The majority of Testosterone products that have been designed are single products that contain a single esterified form (such as this one), as opposed to Testosterone products which consist of a blend of several different esterified variants in the liquid (such as Sustanon 250, for example). Testosterone that is un-esterified holds a very short half-life, making its use very inconvenient and impractical (Testosterone suspension is one such Testosterone product that consists of pure un-esterified Testosterone, and does not have an ester bonded to its structure). The Propionate ester expands Testosterone’s half-life to that of 4.5 days.