Last Updated: January 9 2023

Glutamine is an amino acid that may benefit the body when it is under a period of great physical stress, such as after surgery, burns, or radiation exposure.

Glutamine is most often used for

What is glutamine?

Glutamine is one of the 20 amino acids that make up all proteins. It is conditionally essential, meaning it is needed during traumatic conditions like illness, injury, or surgery. It is the most abundant amino acid in blood serum, and it tends to decrease in proportion to the acuteness of trauma to the body.[88][89]

What are glutamine’s main benefits?

The main benefit of glutamine is improved outcomes in trauma, burns, and injuries.[90] It has also been found to affect nitrogen balance (i.e., reduce protein depletion), improve immune function, and reduce infectious morbidity in adults going in for abdominal surgery for peritonitis (an infection of the abdomen).[91] In addition, glutamine may reduce gut permeability (lactulose/mannitol ratio), inflammation (IL-6, TNF-ɑ, C-reactive protein), hospital stay length, and mortality.[88]

In people undergoing radiation therapy for head and neck cancer, glutamine reduced the severity of oral mucositis. This painful condition results from the death of the cells lining the mouth and is often a reason to halt the course of radiation. Post-radiation, glutamine was found to reduce the use of analgesic opioids, nasogastric feeding, and treatment interruptions.[92]

In addition, glutamine may reduce symptom scores of irritable bowel syndrome (IBS) alongside a low-FODMAP diet.[93] Glutamine was found to have no significant effect in the context of Crohn’s disease, though sample sizes were small.[94][95][96][97]

Glutamine is commonly marketed as an exercise supplement, but there are no consistent observed effects on athletic performance from supplementation with glutamine. However, glutamine may increase white blood cell counts and benefit weight reduction.[98]

What are glutamine’s main drawbacks?

Glutamine typically has no adverse effects.[91][93][92] Even doses as high as 50–60 grams per day taken for several weeks seem to be well tolerated.[99][88]

How does glutamine work?

Glutamine may improve digestion by strengthening the intestinal barrier by reducing intestinal permeability, aiding tight junctions, and promoting enterocyte growth (cells that line the intestines).[90]

Glutamine is the preferred source of fuel for enterocytes as well as lymphocytes, an important cell of the immune system.[93]

Glutamine may act as an anti-inflammatory agent by reducing interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-ɑ), and C-reactive protein levels. It may also help produce glutathione, the body’s principal antioxidant.[90][88]

What else is Glutamine known as?
Note that Glutamine is also known as:
  • L-Glutamine
Glutamine should not be confused with:
Dosage information

Supplementation of L-glutamine tends to be dosed at 5 g or above, with higher doses being advised against due to excessive ammonia in serum. The lowest dose found to increase ammonia in serum has been 0.75 g/kg, or approximately 51 g for a 150 lb individual.

Due to the relative inefficacy of glutamine supplementation for increasing muscle mass, the optimal dosage is not known. The above recommended doses are sufficient for intestinal health reasons and for attenuating a possible relative glutamine deficiency (seen in instances of low protein intake or veganism).

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