Emerging supplements in sports.

Context: Nutritional supplements advertised as ergogenic are commonly used by athletes at all levels. Health care professionals have an opportunity and responsibility to counsel athletes concerning the safety and efficacy of supplements on the market.
Evidence Acquisition: An Internet search of common fitness and bodybuilding sites was performed to identify supplement promotions. A search of MEDLINE (2000-August, 2011) was performed using the most commonly identified supplements, including glutamine, choline, methoxyisoflavone, quercetin, zinc/magnesium aspartate, and nitric oxide. The search terms supplement, ergogenic aid, and performance were also used.
Results: Six common and newer supplements were identified, including glutamine, choline, methoxyisoflavone, quercetin, zinc/magnesium aspartate, and nitric oxide.
Conclusions: Controlled studies have not determined the effects of these supplements on performance in athletes. Scientific evidence is not available to support the use of these supplements for performance enhancement.