In humans, doctors prescribe steroids to treat people who are slow to reach puberty, people with some blood disorders, and those with some types of breast cancer. Anabolic steroids should not be confused with corticosteroids. These are prescribed for asthma and other disorders and do not build muscles. Although anabolic steroids are banned by most professional and amateur sports, many athletes use them to improve their performance in sports requiring strength and power. These sports include track and field, weight lifting and football.
Some men also use steroids to improve their physical appearance.
Users take steroids orally or by injection. Many athletes take doses 5 to 10 times larger than those prescribed medically. Body builders and weight lifters may take doses up to 100 times larger. Steroid users tend to follow a variety of dosing routines. Although selling anabolic steroids for non-medical use is illegal, they are readily available in most gyms.