Glutamine, Gut Health, Immune Function and Critical Illness: Medical Use vs Supplements
Glutamine in hospital care (intensive care, burns, sickle cell disease) versus glutamine powders, with what trials found for gut conditions, immune claims and "leaky gut".
Content last updated . This page has not been medically reviewed.
Glutamine is a conditionally essential amino acid. MedlinePlus says conditionally essential amino acids are usually not essential, except in times of illness and stress. [1] A review describes glutamine as becoming deficient in several stress states, including critical illness, trauma, infection, cancer and gut disorders. [2] That idea is why it was tested in hospitals. Whether the tests helped is a separate question.
Medical use versus supplements
| Setting | What the sources found | Label |
|---|---|---|
| Critically ill adults and major surgery | A Cochrane review of 53 trials (4,671 people) found fewer hospital-acquired infections with glutamine (risk ratio 0.79). [3] Short-term mortality did not differ significantly, and ICU stay was slightly longer in the glutamine group. [3] The review noted that two recent large trials found no benefit. [3] | Mixed |
| Critically ill adults with organ failure | In a trial of 1,223 adults in 40 intensive care units, glutamine was associated with an increase in mortality. [4] | Evidence of possible harm in this group |
| Critical illness, later pooled analysis | A 2021 meta-analysis of 47 trials (6,198 patients) suggested glutamine need not be routinely added to the diet of critically ill patients to reduce hospital mortality, with severe burns as an exception. [5] | Mixed |
| Severe burns | A 2024 meta-analysis of 22 trials (2,170 patients) found a shorter hospital stay and less wound infection, but no improvement in in-hospital mortality; it did not recommend routine use, noting positive effects were based on small single-center studies. [6] A separate 2024 analysis of 6 trials (1,398 patients) found no clear mortality benefit. [7] | Mixed |
| Sickle cell disease | In a 48-week trial of 230 people aged 5 to 58, prescription-grade L-glutamine was linked to fewer pain crises than placebo (median 3 versus 4). [8] The FDA approved a prescription L-glutamine oral powder in 2017 for people aged 5 and over. [9] | Established medical use of a prescription product |
| Short bowel syndrome | A Cochrane review found the evidence inconclusive for growth hormone with or without glutamine. [10] | Insufficient evidence |
All of these are medical settings with monitoring. They do not transfer to a person taking a powder at home.
Gut conditions
| Question | What the sources found | Label |
|---|---|---|
| Post-infectious irritable bowel syndrome with diarrhea (IBS-D) and raised gut permeability | An 8-week placebo-controlled trial gave glutamine (5 g three times a day) or placebo; 54 glutamine and 52 placebo participants completed it, and the glutamine group had much larger improvements in symptom scores. No serious adverse events were observed. [11] The authors said large trials should now validate the findings. [11] | Promising but limited; one trial, one specific condition |
| Inflammatory bowel disease (Crohn's disease, ulcerative colitis) | A systematic review of 7 articles concluded glutamine had no effect on disease course, intestinal permeability, disease activity or symptoms. [12] | No clear benefit found |
| "Leaky gut" in healthy people, general digestion, bloating | Proper evidence not found. We searched PubMed for trials of glutamine and intestinal permeability in healthy people and for systematic reviews of glutamine in gut conditions, and found no usable trials in healthy people. | Insufficient evidence |
| Immune "support" in healthy people | Proper evidence not found. The infection findings above come from hospital patients and cannot be applied to healthy people. | Insufficient evidence |
The IBS-D result applies to people who developed IBS-D after an infection and had increased gut permeability, not to ordinary digestive upset. For the popular "leaky gut" idea see leaky gut, cleanses and gut tests: claim check. For symptoms see irritable bowel syndrome and digestive symptoms: red flags and when to get help. Immune basics are on immune wellness.
Frequently asked questions
Does glutamine heal a leaky gut?
Proper evidence not found for healthy people. The one positive trial we read was in post-infectious IBS-D with raised permeability, and its authors called for larger trials. [11]
Is glutamine given in intensive care?
It has been tested there. A Cochrane review found fewer infections but no clear difference in deaths, and a large trial in organ failure found more deaths with glutamine. [3][4]
Does glutamine help burns?
A 2024 meta-analysis found shorter hospital stays but did not recommend routine use. [6]
Is glutamine approved for sickle cell disease?
In the US, the FDA approved a prescription L-glutamine oral powder for people aged 5 and over with sickle cell disease. [9] It is a medical product, not a general supplement.
Does glutamine help inflammatory bowel disease?
A systematic review of 7 articles found no effect on disease course or activity. [12]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Side effects and safety
- Hospital use is clinician-led. Never use glutamine as a substitute for care for severe illness, burns, blood in stool, weight loss or lasting diarrhea.
- Sickle cell trial. Low-grade nausea, chest pain not from the heart, fatigue and musculoskeletal pain occurred more often with glutamine than placebo. [8]
- Kidneys and diabetes. A review reported glutamine can cause glomerulosclerosis and a rise in serum creatinine in diabetic kidney disease. [13]
- Amounts. A risk assessment found strong evidence of no adverse effects for healthy adults at supplemental glutamine up to 14 g a day, and said higher intakes lacked enough data. [14] Study amounts here are not advice; no official recommended intake was found.
- Medicines, pregnancy, children, liver disease and surgery. Not described in the sources we read. Ask a clinician or pharmacist. See how interactions work and supplements before surgery.
References
- MedlinePlus. Amino acids. National Library of Medicine, US (reviewed 1/21/2025). Read 2026-10-22.
- Morris CR et al. Acquired amino acid deficiencies: a focus on arginine and glutamine. Nutr Clin Pract 2017. Read 2026-10-22.
- Tao KM et al. Glutamine supplementation for critically ill adults. Cochrane Database Syst Rev 2014. Read 2026-10-22.
- Heyland D et al. A randomized trial of glutamine and antioxidants in critically ill patients. N Engl J Med 2013. Read 2026-10-22.
- Sun Y et al. Glutamine on critical-ill patients: a systematic review and meta-analysis. Ann Palliat Med 2021. Read 2026-10-22.
- Tao W et al. Glutamine supplementation on burn patients: a systematic review and meta-analysis. J Burn Care Res 2024. Read 2026-10-22.
- Yue HY et al. Enteral glutamine supplements for patients with severe burns: a systematic review and meta-analysis. Chin J Traumatol 2024. Read 2026-10-22.
- Niihara Y et al. A phase 3 trial of L-glutamine in sickle cell disease. N Engl J Med 2018. Read 2026-10-22.
- FDA. FDA approves new treatment for sickle cell disease. US Food and Drug Administration, July 7, 2017. Read 2026-10-23.
- Wales PW et al. Human growth hormone and glutamine for patients with short bowel syndrome. Cochrane Database Syst Rev 2010. Read 2026-10-22.
- Zhou Q et al. Randomised placebo-controlled trial of dietary glutamine supplements for postinfectious irritable bowel syndrome. Gut 2019. Read 2026-10-22.
- Severo JS et al. Effects of glutamine supplementation on inflammatory bowel disease: a systematic review of clinical trials. Clin Nutr ESPEN 2021. Read 2026-10-22.
- Davani-Davari D et al. The renal safety of L-carnitine, L-arginine, and glutamine in athletes and bodybuilders. J Ren Nutr 2019. Read 2026-10-22.
- Shao A, Hathcock JN. Risk assessment for the amino acids taurine, L-glutamine and L-arginine. Regul Toxicol Pharmacol 2008. Read 2026-10-22.