These sports include bodybuilding, weightlifting, shot put and other track and field, cycling, baseball, wrestling, mixed martial arts, boxing, football, and cricket.
Such use is prohibited by the rules of the governing bodies of most sports.
A number of severe side effects can occur if adolescents use AAS.
For example, AAS may prematurely stop the lengthening of bones (premature epiphyseal fusion through increased levels of estrogen metabolites), resulting in stunted growth.
In order to be sufficiently active when given by mouth, testosterone derivatives are alkylated at the 17α position, e.g. This modification reduces the liver's ability to break down these compounds before they reach the systemic circulation.
"Among 12- to 17-year-old boys, use of steroids and similar drugs jumped 25 percent from 1999 to 2000, with 20 percent saying they use them for looks rather than sports, a study by insurer Blue Cross Blue Shield found."(Eisenhauer) Another study found that non-medical use of AAS among college students was at or less than 1%.
Injection is the most common method used by individuals administering AAS for non-medical purposes.
The traditional routes of administration do not have differential effects on the efficacy of the drug.
Transdermal patches (adhesive patches placed on the skin) may also 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 also available, but absorption is inefficient (roughly 10%, varying between individuals) and these treatments tend to be more expensive.