Lglutamine

L-glutamine is the L-enantiomer of the amino acid glutamine, a conditionally essential amino acid in humans. It is one of the most abundant free amino acids in plasma and skeletal muscle and participates in protein synthesis, nitrogen transport, and various metabolic processes.

Biosynthesis and metabolism: It is synthesized from glutamate and ammonia by the enzyme glutamine synthetase, using ATP. In tissues, glutaminase converts it back to glutamate and ammonium as needed. In the gut, enterocytes use glutamine as a major energy source and to support mucosal integrity; immune cells also rely on it during activation. Glutamine serves as a nitrogen donor for nucleotide and amino sugar synthesis and acts as a precursor for the antioxidant glutathione and for polyamines.

Biological roles: Beyond its role in biosynthesis, glutamine helps regulate acid-base balance, provides carbon and nitrogen for multiple pathways, and supports rapidly dividing cells in the gut and immune system. It is the most abundant free amino acid in plasma and plays a central role in nitrogen transport between tissues.

Clinical and dietary aspects: L-glutamine is obtained from dietary protein and is available as a supplement. In healthy individuals, supplementation is not required. In clinical contexts involving severe stress, trauma, burns, or critical illness, glutamine may be provided as part of specialized nutrition regimens, though evidence for clear outcome benefits is mixed and recommendations vary. High-dose supplementation can cause adverse effects, and caution is advised for people with kidney or liver conditions.