The resulting unnatural level of red blood cells improves oxygen transport and athletic endurance; thus, it is prohibited in most events.
Other banned anabolic agents include clenbuterol, tibolone, zeranol, zilpaterol, and selective androgen receptor modulators.
Also banned are any other growth factor affecting muscle, tendon or ligament protein synthesis/degradation, vascularization, energy utilization, regenerative capacity or fiber type switching, and other substances with similar chemical structure and/or biological effects.
Because of these natural hormone-hormone interdependent biosynthetic pathways and hormone-receptor interactions, all aromatase inhibitors, including anastrozole, letrozole, aminoglutethimide, exemestane, formestane, and testolactone are banned.
[7]: 4 Diuretics, which increase the production of urine, and masking agents, chemical compounds which interfere with drug tests, are banned for two reasons.
Desmopressin, plasma expanders (such as glycerol; intravenous administration of albumin, dextran, hydroxyethyl starch and mannitol), probenecid, and other substances with similar biological effects are also banned.
[7]: 5 The following diuretics, and chemicals with similar structure or biological activity are banned: Stimulants directly affect the central nervous system, increasing blood flow and heart rate.
Stimulants that are banned in competition only include amphetamines, beta-2 agonists, ephedrine, pseudoephedrine, fencamfamine, cocaine, methamphetamines, mesocarb, and other substances with similar chemical structures and biological effects, including the following:[7]: 6 Narcotic analgesics decrease the painful sensations of serious injuries, potentially allowing athletes to continue training for competition after an injury.
[11][7]: 7 Glucocorticoids are a class of corticosteroids that affect the metabolism of carbohydrates, fat, and proteins, and regulate glycogen and blood pressure levels.
Because of this and metabolic regulation effects, the administration of any glucocorticoid orally, rectally, intravenously, or intramuscularly is prohibited in competition only and requires a therapeutic use exemption.
Therapeutic use exemption (TUE) is a term used by WADA and the United States Anti-Doping Agency to denote banned substances that athletes may be "required to take to treat an illness or condition".
The detection of such substances in samples is labelled by WADA as an "adverse analytical finding" (AAF), which is distinct from "anti-doping rules violations" (ADRV).