Method of treating extreme physical or mental stress using L-theanine to obtain accelerated regeneration

Method of using L-Theanine for acceleration of regeneration after stressing. A quantity of at least 50 mg of L-Theanine is administered after physical or mental stressing. For example, L-Theanine can be administered in the form of a food stuff, such as a functional food with L-Theanine additive, or in the form of a complete drink.