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.
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. 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.
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.
Side Effects (Estrogenic):
Testosterone is readily aromatized in the body to estradiol (estrogen). The aromatase (estrogen synthetase) enzyme is responsible for this metabolism of testosterone. Elevated estrogen levels can cause side effects such as increased water retention, body fat gain, and gynecomastia. Testosterone is considered a moderately estrogenic steroid. An anti-estrogen such as clomiphene citrate or tamoxifen citrate may be necessary to prevent estrogenic side effects. One may alternately use an aromatase inhibitor like Arimidex® (anastrozole), which more efficiently controls estrogen by preventing its synthesis. Aromatase inhibitors can be quite expensive in comparison to anti-estrogens, however, and may also have negative effects on blood lipids. Estrogenic side effects will occur in a dose-dependant manner, with higher doses (above normal therapeutic levels) of testosterone propionate more likely to require the concurrent use of an anti-estrogen or aromatase inhibitor. Since water retention and loss of muscle definition are common with higher doses of testosterone, this drug is usually considered a poor choice for dieting or cutting phases of training. Its moderate estrogenicity makes it more ideal for bulking phases, where the added water retention will support raw strength and muscle size, and help foster a stronger anabolic environment.
Side Effects (Androgenic):
Testosterone is the primary male androgen, responsible for maintaining secondary male sexual characteristics. Elevated levels of testosterone are likely to produce androgenic side effects including oily skin, acne, and body/facial hair growth. Men with a genetic predisposition for hair loss (androgenetic alopecia) may notice accelerated male pattern balding. Those concerned about hair loss may find a more comfortable option in nandrolone decanoate, which is a comparably less androgenic steroid. Women are warned of the potential virilizing effects of anabolic/androgenic steroids, especially with a strong androgen such as testosterone. These may include deepening of the voice, menstrual irregularities, changes in skin texture, facial hair growth, and clitoral enlargement. In androgen-responsive target tissues such as the skin, scalp, and prostate, the high relative androgenicity of testosterone is dependant on its reduction to dihydrotestosterone (DHT).
The 5-alpha reductase enzyme is responsible for this metabolism of testosterone. The concurrent use of a 5-alpha reductase inhibitor such as finasteride or dutasteride will interfere with site-specific potentiation of testosterone action, lowering the tendency of testosterone drugs to produce androgenic side effects. It is important to remember that both anabolic and androgenic effects are mediated via the cytosolic androgen receptor. Complete separation of testosterone’s anabolic and androgenic properties is not possible, even with total 5-alpha reductase inhibition.
Side Effects (Hepatotoxicity):
Testosterone does not have hepatotoxic effects; liver toxicity is unlikely. One study examined the potential for hepatotoxicity with high doses of testosterone by administering 400 mg of the hormone per day (2, mg per week) to a group of male subjects. The steroid was taken orally so that higher peak concentrations would be reached in hepatic tissues compared to intramuscular injections. The hormone was given daily for 20 days, and produced no significant changes in liver enzyme values including serum albumin, bilirubin, alanine-amino-transferase, and alkaline phosphatases.
• 4-androstene-3-one, 17beta-ol
• Testosterone base + Propionate ester
• Molecular Weight (base): 288.429
• Molecular Weight (ester): 74.0792
• Formula (base): C19 H28 O2
• Formula (ester): C3H6O2
• Melting Point (base): 155
• Melting Point (ester): 21C
• Manufacturer: Various
• Effective Dose (Men): 350-2000mg+ week.
• Effective Dose (Women): 50-100mgs/week
• Active life: 2-3 days
• Detection Time: 2-3 weeks
• Anabolic/Androgenic ratio:100/100.