Testosterone cypionate is a slow-acting injectable ester of the primary male androgen testosterone. Testosterone is also the principle anabolic hormone in men, and is the basis of comparison by which all other anabolic/androgenic steroids are judged. As with all testosterone injectables, testosterone cypionate is highly favored by athletes for its ability to promote strong increases in muscle mass and strength. It is interesting to note that while a large number of other steroidal compounds have been made available since testosterone injectables, they are still considered to be the dominant bulking agents among bodybuilders. There is little argument that these are among the most powerful mass drugs available, testosterone cypionate included.
Testosterone cypionate first appeared on the U.S. drug market during the mid-1950’s under the brand name of Depo- Testosterone cyclopentylpropionate (soon abridged to simply Depo-Testosterone). It was developed by the pharmaceutical giant Upjohn, and is still sold to this day by the same company under the same trade name (although now they are called Pharmacia & Upjohn). This is a drug with limited global availability, and has historically been (largely) identified as an American item. It is not surprising that American athletes have long favored this form of testosterone over testosterone enanthate, the dominant slow-acting ester of testosterone on the global market. This preference, however, is likely rooted in history and availability, not actual therapeutic advantages. Testosterone cypionate and testosterone enanthate provide extremely comparable patterns of testosterone release. Not only are physical advantages not possible in one over the other, but actual differences in pharmacokinetic patterns are hard to notice (these two drugs are for all intents and purposes functionally interchangeable). The only key difference between the two seems to be in the area of patient comfort.
Testosterone cypionate is a modified form of testosterone, where a carboxylic acid ester (cyclopentylpropionic 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 cypionate is approximately 8 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 cypionate 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 cypionate, 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 anabolic and androgenic effects are both 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.
• Testosterone base + cypionate ester
• Formula: C27 H40 O3
• Molecular Weight: 412.6112
• Molecular Weight (base): 288.429
• Molecular Weight (ester): 132.1184
• Formula (base): C19 H28 O2
• Formula (ester): C8 H14 O2
• Melting Point (base): 155
• Melting Point (ester): 98 – 104 C
• Manufacturer: Various
• Effective Dose (Men): 300-2000mg+ week
• Effective Dose (Women): Not recommended
• Active life: 8 days
• Detection Time: 3 months
• Anabolic/Androgenic ratio: 100/100.