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 . 
Users on an oral steroid cycle may experience a sudden increase in body weight and muscular development, insomnia, irritability, aggressive combative behavior, puffy face, severe acne, bad breath, a yellowing of the eyes and skin, premature hair loss, hyperactivity, and exaggerated mood swings that include uncontrollable outbursts of anger. Males may also experience testicular shrinkage and can develop female breast tissue on the pectoral muscles. Females may also experience a deeper voice and decreased breast size. Continued use can result in life-threatening situations involving the liver, cardiovascular system, and brain.