Definition:   L-Glutamine (hereinafter called glutamine) is the most abundant free amino acid in the body.

• It is a preferred source of fuel for the small intestinal mucosa and plays a key role in maintaining small intestinal structure and function.
• Glutamine is also an important fuel for some cells of the immune system and may have specific immunostimulatory effects.
• In addition, glutamine is involved in the transport of circulating amino nitrogen.
• Most of the endogenously produced glutamine is synthesized and stored in skeletal muscle (from glutamate), where its concentration is 30 times greater than in serum.
• Glutamine may be useful for preventing and/or treating acquired immunodeficiency syndrome, alcohol addiction, burns, critical illness, gastroenteritis, pancreatitis, and peptic ulcer, and for preventing infections following intense physical exercise.
• Large doses of glutamine should not be given to patients with impaired liver function.
• Glutamine supplementation may exacerbate Crohn’s disease, even though glutamine is an important source of fuel for small intestinal cells.
• Numerous studies have found that supplementation with large doses of glutamine can prevent or reduce the severity of various chemotherapy side effects, without apparently interfering with the anticancer effect of chemotherapy.

Dosage and administration

The dosage of oral glutamine used in clinical trials has varied widely, from 1 g/day to 30 g/day or more.