Effect of clenbuterol on athletic performance.
Unlike inhaled beta 2-agonists, more studies need to be performed before the action of systemic beta 2-agonists on athletic performance can be assessed accurately. Experiments in animals with oral clenbuterol have shown augmentation in muscle bulk across numerous species, but human studies cannot confirm similar muscle mass enlargement in healthy men. Although the human studies demonstrate the potential for long-acting systemic beta 2-agonists to increase muscle strength in certain muscle fiber types, it is difficult to judge the drugs' effects on overall athletic performance, because athletic skill is more than strength, speed, and endurance. The effect of oral clenbuterol on athletic performance cannot be evaluated from its actions on muscle strength alone. However, as evidence stands now, sports regulatory agencies are correct to ban systemic beta 2-agonists until the following 2 points can be proven: (1) oral forms provide a therapeutic benefit that cannot be obtained with aerosol or inhaled forms; and (2) oral forms do not give any unfair advantage to the competitor in muscle strength, power output, or endurance. Provided they are administered as prescribed, aerosol or inhaled beta-agonists do not impart an unfair advantage or enhance athletic performance and can continue to be used in competition by athletes with EIA.