>Caffeine is considered the most popular psychoactive drug used by the majority of the general population in the world. Due to its ergogenic effect, it is widely used by athletes of many sports disciplines.
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>Interestingly, between 1984 and 2004 caffeine was banned in sports competitions, although only in extremely high doses (i.e., representing a concentration of caffeine greater than 12 μg/mL in urine). However, on 1 January 2004, the World Anti-Doping Agency (WADA) decided to remove caffeine from the list of banned substances. Since then, athletes can freely use this substance during competitions. Nevertheless, caffeine has been moved to the Monitoring Program to control the consumption of high doses of caffeine by athletes (i.e., over 6 μg/mL in urine) as they can be harmful to them.
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>Interestingly, a urinary caffeine concentration greater than 15 µg/mL is still prohibited by the National Collegiate Athletic Association (NCAA). However, since the ban was lifted for almost all associations, caffeine-containing supplements have been hugely popular in the sports world. It has been shown that up to 75–90% of athletes use caffeine before or during competition. The recommended doses of caffeine intake by athletes are 3–6 mg/kg body mass (BM). This is due to the fact that higher doses of caffeine (9–13 mg/kg BM) do not result in additional benefits, and also increase the risk of side effects.