Glutamine is a nonessential amino acid. About 60% of all unbound amino acids in skeletal muscles are glutamine. In normal circumstances, the body produces more than enough of on its own, but strenuous workouts and stress drain more from the body than it is capable of producing. In the body, it is responsible for the positive nitrogen balance, which is a prerequisite for the recovery of muscle tissue micro-injuries caused by physical exertion. Glutamine plays a very important role in protein synthesis, muscle regeneration and physical resilience. If the body is not provided with sufficient glutamine, or if it cannot produce as much as it needs, the internal organs and the immune system take it from the muscles which consequently fall into a catabolic state. In particular, when intense workouts and exercises with weights are concerned, its level in the body can be reduced up to 50%, resulting in a decrease of muscle tissue and poor regeneration.