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 . 
The Story: In February 2005 Canseco released his autobiography and steroid tell-all, Juiced , Wild Times, Rampant 'Roids, Smash Hits, and How Baseball Got Big. In it he described himself as 'the chemist' having experimented on himself for years. He claimed to have educated and personally injected many players including Mark McGwire, Rafael Palmeiro, Juan Gonzalez, Ivan Rodriguez, and Jason Giambi. In his second book, Vindicated , Canseco added Magglio Ordonez to the list of players he had educated and injected with steroids. He also said he introduced Alex Rodriguez to a trainer/PED supplier after Rodriguez had asked where he could get steroids.
Tetrahydrogestrinone (THG) - Commonly known as The Clear, Tetrahydrogestrinone (THG is a type of steroid that had only been recently placed into scheduling as of 2005 and is noted unapproved by FDA. It basically binds with the androgen receptor instead of estrogen which makes it effective in increasing endurance for athletes. According to history, this was the secret of winning for the gold medalist Marion Jones, a sprinter athlete. However, longer association with this type of steroid can lead to infertility in both male and female. Using the steroids abuse test kit, a person may be held liable for a positive THG steroid test.