Anabolic-androgenic steroids — commonly known as steroids — are synthetic substances made from the male hormone testosterone. Steroid use has been officially condemned by most national and international sports organizations because of the overwhelming evidence that steroids can cause dangerous side effects and do not increase long-term athletic performance.

Sixty to eighty percent of steroids used are obtained through the black market. Users are often unaware of the drugs’ harmful side effects. Steroids are sometimes used in the treatment of certain medical disorders, including deficient hormonal functioning of the testes, anaemia, and growth retardation in children, breast cancer, osteoporosis, and hereditary fluid retention. Their use is controversial, and some patients can be affected by their harmful side effects.

In females, steroid use causes acne and masculinization, which can include growth of facial hair, deepening of the voice, menstrual problems, baldness, excessive body hair growth, and prominent musculature. In males, steroid use can cause balding, acne, decreased sperm production, shrinking testes, and enlargement of breast tissue. Violent, combative moodiness, depression, delusions, paranoia, and suicidal feelings are also associated with steroid use.

Steroid users are at increased risk for developing water retention, abnormal skeletal muscle changes, liver dysfunction, liver cancer, and premature heart diseases. Long-term use may cause irreversible organ damage and death.

Steroid use is particularly harmful to young people who are still maturing physically. These drugs can stunt growth and disrupt normal sexual development. Use of steroids during pregnancy can cause severe damage to the developing foetus, particularly to female foetuses.