Anabolic androgenic steroids (AAS) were initially created for therapeutic purposes, and synthetic derivatives of the male hormone testosterone. Due its great anabolic effects, these drugs are being used on a large scale, for the improvement of sports performance. In this present study, we aim to show the history of it’ use, present their mechanisms of action, more particularly its use correlate with improved body composition, muscle mass, aerobic capacity and verify their possible side effects, analyzing their use therapeutic and indiscriminate, through direct scientific research with the sports. Sources were reviewed scientific the following search engines: PUBMED, LILACS and SCIELO. The results showed that in presence of a suitable AAS and diet can contribute to increases in body weight, particularly lean body mass and muscle strength gains achieved by high intensity exercise, these effects can be further potentiated, the use of supraphysiological doses, but in the aspect of aerobic power, there are not scientific evidence to support their improvement. Regarding side effects, the use of AAS, is related to several complications in the liver, cardiovascular system, reproductive system and psychological characteristics, always assigned by the non-therapeutic and abuse of AAS. Thus we conclude that the use of AAS, are directly linked to gains muscle mass, strength, as well several side effects, always assigned to abusive and indiscriminate doses, it is noteworthy that the scientific literature, still has a certain lack of studies, mainly randomized, controlled, with supraphysiological doses in human, so many effects are still unknown.
Testosterone can be administered parenterally , but it has more irregular prolonged absorption time and greater activity in muscle in enanthate , undecanoate , or cypionate ester form. These derivatives are hydrolyzed to release free testosterone at the site of injection; absorption rate (and thus injection schedule) varies among different esters, but medical injections are normally done anywhere between semi-weekly to once every 12 weeks. A more frequent schedule may be desirable in order to maintain a more constant level of hormone in the system.  Injectable steroids are typically administered into the muscle, not into the vein, to avoid sudden changes in the amount of the drug in the bloodstream. In addition, because estered testosterone is dissolved in oil, intravenous injection has the potential to cause a dangerous embolism (clot) in the bloodstream.
Non-medical users of anabolic steroids often “stack” different anabolic steroids over the course of a “cycle” of use. They also administer various ancillary drugs and substances to enhance the desired effects of anabolic steroids or to minimize adverse side effects. The most common liquid (injectable) anabolic steroids encountered in these cases are (oil-based) esters of testosterone (., testosterone cypionate, testosterone enanthate, and testosterone propionate, and a blend of testosterone esters called Sustanon 250) or nandrolone (., nandrolone decanoate). Also popular are Equipoise (boldenone undecylenate) and trenbolone acetate and trenbolone enanthate, as well as the water-based injectable Winstrol (stanozolol). Popular oral anabolic steroids include methandrostenolone (Dianbol), oxandrolone (Anavar) and oxymetholone (Anadrol 50).