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 . 
Soon after the famous record by Roger Maris was beaten, another baseball player, Jason Giambi and others came out to say they often used prohormones. The Congress was forced to convene a hearing after which it determined that steroids were not really a threat. Rather, it ruled out that it was the responsibility of professional sports organizations to supervise and regulate their use. The law was updated and an official definition of the term steroid was given as follow: an “anabolic steroid” means any drug or hormonal substance, chemically and pharmacologically related to testosterone (other than estrogens), progestins, corticosteroids, and dehydroepiandrosterone).
Transdermal patches (adhesive patches placed on the skin) might additionally be used to deliver a steady dose through the skin and into the bloodstream. Testosterone-containing creams and gels that are applied daily to the skin are additionally available, but absorption is inefficient (roughly 10%, varying between individuals) and these treatments tend to be more expensive. Individuals who're especially physically active and/or bathe most often might not be good candidates, after the medication can be washed off and might take up to six hours to be fully absorbed. There is additionally the risk that an intimate partner or child might come in contact with the application site and inadvertently dose himself or herself; children and women are highly sensitive to testosterone and can suffer unintended masculinization and health effects, even from small doses. Injection is the most common method used by individuals administering anabolic steroids for non-medical purposes.