The gains made by athletes in uncontrolled observations have been much more impressive. Weight gains of thirty or forty pounds, coupled with thirty percent increases in strength, are not unusual. Such case studies lack credibility because of the absence of scientific controls. However, it would be foolish to completely disregard such observations because the "subjects" have been highly trained and motivated see the articles on pharmacology of sport and sports medicine in the countries of the former Soviet Union for more information on anabolic steroids.
The most commonly used AAS in medicine are testosterone and its various esters (but most commonly testosterone undecanoate , testosterone enanthate , testosterone cypionate , and testosterone propionate ),  nandrolone esters (most commonly nandrolone decanoate and nandrolone phenylpropionate ), stanozolol , and metandienone (methandrostenolone).  Others also available and used commonly but to a lesser extent include methyltestosterone , oxandrolone , mesterolone , and oxymetholone , as well as drostanolone propionate , metenolone (methylandrostenolone), and fluoxymesterone .  Dihydrotestosterone (DHT; androstanolone, stanolone) and its esters are also notable, although they are not widely used in medicine.  Boldenone undecylenate and trenbolone acetate are used in veterinary medicine .