Steroid abuse

Steroid abuse describes the side effects of using anabolic steroids like testosterone or human growth hormone  for non-therapeutic purposes.  These pharmaceuticals quickly build the mass of muscles - far faster than exercise alone.  
However, the drugs have both short-term and long-term side effects:
*As part of the body's feedback system, large doses of testosterone reduce the production of testosterone in the testicles, leading to hypogonadism.
*Secondary male sexual characteristics are enhanced, particularly when the drugs are used by females.  This leads to the growth of body hair and the deepening of the voice.
*The drugs interfere with the metabolism, often causing organ damage, particularly to the kidneys.
In most cases, the effects are reversible when the drugs are discontinued, although they should be tapered off until the body starts producing testosterone on its own.  
Ergogenic use of anabolic steroids at Wikipedia