Function: Glutamine is used for energy, for synthesis of other essential building blocks, (protein, DNA, and RNA), and for removal of toxic substances. Glutamine is a dispensable amino acid present in greater amounts than any other amino acid in the body fluid and cells. In addition to being incorporated into proteins, Glutamine has many metabolic functions: major component of amino acid pools, alternative energy source, DNA and RNA synthesis precursor, neurotransmitter precursor, acid/base balance, ureagenesis, and precursor for other dispensable amino acids, amino sugars and other compounds. Deficiency Symptoms Glutamine deficiency symptoms are not described because of endogenous synthesis and high dietary intakes. However, certain conditions are under investigation where exogenous supply of glutamine may become essential: intestinal disorders, major trauma (burns, surgery), immune functions, gastric ulcers. Glutamine may be useful in alcoholism and fatigue. Repletion Information: No RDA exists for glutamine, which occurs in large amounts in foods containing protein. Richest sources are milk protein and meats. Large doses of glutamine, as the free-form amino acid (up to 10 grams daily) appear to be well tolerated. Larger doses may cause osmotic diarrhea in some persons and are contraindicated in hyperammonemia.