EAA - a complex of amino acids and conditionally essential supplied with food and nutritional supplements, because it is not possible to synthesizing them intracorporeally. Essential amino acids of the EAA complex are: phenylalanine, tryptophan, valine, isoleucine, leucine, lysine, threonine and methionine, conditionally essential - histidine and arginine are necessary to ensure the accuracy of life processes involving the exchange of proteins. For the sports supplementation it is a fundamental component of a dietary supplement, supporting exercise capacity in sport strength-endurance. Depending on the chemical composition they work both catabolic and anti-catabolic. It is particularly important to supplement the EAA immediately after a heavy workout. In combination with carbohydrates they are most effective in the post-workout recovery.