It has been suggested that the prevalence of use among high-school students in the U. 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.
They are anabolic and increase protein within cells, especially in skeletal muscles, and also have varying degrees of androgenic and virilizing effects, including induction of the development and maintenance of masculine secondary sexual characteristics such as the growth of the vocal cords and body hair.Studies indicate that the anabolic properties of AAS are relatively similar despite the differences in pharmacokinetic principles such as first-pass metabolism.However, the orally available forms of AAS may cause liver damage in high doses.Conditions pertaining to hormonal imbalances such as gynecomastia and testicular size reduction may also be caused by AAS. Ergogenic uses for AAS in sports, racing, and bodybuilding as performance-enhancing drugs are controversial because of their adverse effects and the potential to gain unfair advantage in physical competitions.Their use is referred to as doping and banned by most major sporting bodies.