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Testosterone Propionate - Anabolic.org
Description:
Testosterone propionate is a commonly manufactured injectable form of the primary male androgen testosterone. The added propionate ester will slow the rate in which testosterone is released from the injection site, but only for a few days. Testosterone propionate is, therefore, comparatively much faster-acting than other testosterone esters such as cypionate or enanthate, and requires a much more frequent dosing schedule. By most accounts testosterone propionate is an older and cruder form of injectable testosterone, made obsolete by the slower-acting and more comfortable esters that were developed subsequent to it. Still, those who are not bothered by the frequent injection schedule find testosterone propionate every bit as acceptable. As an injectable testosterone, it is a powerful mass-building drug, capable of producing rapid gains in both muscle size and strength.
History:
Testosterone propionate was first described in 1935, during a series of experiments that set out to increase the therapeutic usefulness of testosterone by slowing its release into the bloodstream.566 Two years later, Schering AG in Germany would introduce the first testosterone propionate product under the brand name Testoviron®. Propionate was also the first commercially available injectable ester of testosterone on the U.S. prescription drug market, and remained the dominant form of testosterone globally before 1960. Back during the early 1950’s, for example, when steroids were first being experimented with by small numbers of American athletes, the only readily available anabolic/androgenic steroids were methyltestosterone, testosterone propionate, and testosterone suspension. Interesting enough, during this time testosterone propionate was also available in orally administered (Buccal) preparations, but they disappeared from the U.S. market during the 1980’s.
Early prescribing guidelines for testosterone propionate called for a number of therapeutic uses. It was mainly applied to cases of male androgen insufficiency, and those issues normally surrounding low testosterone levels such as reduced sex drive and impotence in adults, and cryptorchidism (undescended testicles) in teenagers and young adults. But it also had such other uses as treating menopause, menorrhagia (heavy menstrual bleeding), menstrual tension, chronic cystic mastitis (fibrocystic breasts), endometriosis, and excessive lactation, covering a wide range of situations in which the male hormone testosterone was being applied to female patients. Over the years these wide guidelines were narrowed by the U.S. Food & Drug Administration, however, and by the 1980’s, testosterone propionate was being largely applied only to male patients.
Testosterone propionate has a long history of availability in the U.S. and abroad, and remains a very common form of testosterone on the global market to this day. It must be emphasized, however, that its ability to remain on the market is more a product of history than unique application. Testosterone propionate was the first acceptable ester of testosterone, and consequently has many decades of history as a useable therapeutic agent. Many companies have sold it for decades now, and so long as it is still in demand will continue to do so. But other (more modern) forms of testosterone such as enanthate and cypionate are much more popular today, as they are much slower-acting still, and allow for far more comfortable administration schedules. Testosterone propionate is still approved for sale in the United States, although its ultimate market future here remains questionable.
Bodybuilders commonly consider propionate to be the mildest testosterone ester, and the preferred form of this hormone for dieting/cutting phases of training. Some will go so far as to say that propionate will harden the physique, while giving the user less water and fat retention than one typically expects to see with a testosterone like enanthate, cypionate or Sustanon.
Realistically, however, these advantages do not hold up to close scrutiny. The propionate ester is actually removed before the testosterone it carries is active in the body, and ultimately has little effect outside of slowing steroid release. It all really boils down to how much testosterone you are getting into your blood with each particular esterified compound. Otherwise, there are no real functional differences between them.
Structural Characteristics:
Testosterone propionate is a modified form of testosterone, where a carboxylic acid ester (propionic acid) has been attached to the 17-beta hydroxyl group. Esterified forms of testosterone are less polar than free testosterone, and are absorbed more slowly from the area of injection. Once in the bloodstream, the ester is removed to yield free (active) testosterone. Esterified forms of testosterone are designed to prolong the window of therapeutic effect following administration, allowing for a less frequent injection schedule compared to injections of free (unesterified) steroid. The half-life of testosterone propionate is approximately two days after injection.
Figure 1. Pharmacokinetics of 25 mg labeled testosterone propionate injection. Source: Pharmacokinetic properties of testosterone propionate in normal men. Fujioka M, Shinohara Y,Baba S. et.Al. J Clin Endocrinol Metab 63 (1986):1361- 4
