Testosterone valerate, or testosterone pentanoate, is a synthetic, steroidal androgen. It is a short-to-medium duration C17β valerate ester of testosterone, with a terminal half-life of approximately twice that of the short-acting testosterone propionate. Testosterone valerate is available exclusively as a component of the veterinary drug Deposterona developed by Syntex Animal Health Company, which is marketed in Mexico. Deposterona also contains testosterone acetate and testosterone undecanoate and is used to treat impotence, weakness, fatigue and hypogonadism in male breeding animals (cows, pigs, canines, sheep), as well as a general protein-sparing anabolic. It is administered via intramuscular injection and acts as a long-lasting prodrug of testosterone. Esterified forms of testosterone are designed to prolong the window of therapeutic effect following administration, allowing for less frequent injection schedule compared to injections of unesterified steroid. Deposterona is also used for bodybuilding purposes in men and not recommended for women performance-enhancing purposes due to its strong androgenic nature, side effects, and slow-acting characteristics (making blood levels difficult to control). Deposterona is only known to be manufactured in Mexico. Because it contains a low concentration of steroid,this product is not in high demand, and not readily diverted for illicit sale.