Glutamine is a nonessential amino acid. Glutamine can donate the ammonia on its side chain to the formation of urea (for eventual excretion by the kidneys) and to purines (necessary for the synthesis of nucleic acids). ... Glutamine may become a conditionally essential amino acid during certain catabolic states.
Glutamine plays a role in a variety of biochemical functions: Protein synthesis, as any other of the 20 proteinogenic amino acids. Lipid synthesis, especially by cancer cells. Regulation of acid-base balance in the kidney by producing ammonium.
Glutamine might help gut function, the immune system, and other essential processes in the body, especially in times of stress. It is also important for providing "fuel" (nitrogen and carbon) to many different cells in the body.
