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 legal status of anabolic steroids varies from country to country. In the ., anabolic steroids are listed as Schedule III controlled substances under the Controlled Substances Act , which makes the possession of such substances without a prescription a federal crime punishable by up to seven years in prison.  In Canada, anabolic steroids and their derivatives are part of the Controlled drugs and substances act and are Schedule IV substances, meaning that it is illegal to obtain or sell them without a prescription. However, possession is not punishable, a consequence reserved for schedule I, II or III substances. Those guilty of buying or selling anabolic steroids in Canada can be imprisoned for up to 18 months. Importing or exporting anabolic steroids also carry similar penalties.  Anabolic steroids are also illegal without prescription in Australia,  Argentina, Brazil, and Portugal,  and are listed as Schedule 4 Controlled Drugs in the United Kingdom.