L-Glutamine is the body’s most plentiful free-form amino acid, and is central in sustaining gastrointestinal function. Glutamine is a significant carrier of nitrogen within the body, which is essential in the cellular healing. Even though glutamine can be manufactured by the intestinal mucosa, during periods of physical stress the body may not produce enough of this on its own. The deficit of glutamine can result in epithelial atrophy, necrosis and ulceration of the gut. Glutamine and intestinal barrier function.