Glutamine
Glutamine is a conditionally essential amino acid, not an essential one. See what trials show for hospital care, sickle cell disease, gut and muscle claims, plus safety limits.
Content last updated . This page has not been medically reviewed.
What is Glutamine good for?
What the body uses it for, and how strong the evidence is. A normal job in the body is not proof that extra supplements add benefit; each card says which.
Normal role as a building block and fuel
Established roleGlutamine is one of the most abundant amino acids in the body. The body makes it, and uses it in protein building and as a fuel and nitrogen carrier.
Supplements: This normal role does not show that extra glutamine from supplements gives any added benefit in healthy people.
Needed more during serious illness and stress
Deficiency linkMedlinePlus lists glutamine as conditionally essential: usually not needed from food, but it may be needed in illness and stress. Levels can fall in critical illness, trauma, infection, cancer and gut disorders.
Supplements: Relevant to hospital care. It does not show that healthy people need a supplement.
Fewer infections in hospital patients (given by hospital teams)
Clinically supportedA Cochrane review of 53 trials in critically ill or major-surgery patients found fewer hospital-acquired infections with glutamine. Deaths did not clearly differ.
Supplements: Evidence is for supervised hospital use; the review rated overall risk of bias as high. A later large trial in people with organ failure found more deaths with glutamine.
Fewer pain crises in sickle cell disease (prescription product)
Clinically supportedIn a 48-week trial of 230 people with sickle cell anaemia or sickle beta-zero thalassaemia, pharmaceutical-grade L-glutamine was linked to fewer pain crises and hospital stays than placebo.
Supplements: Applies to people with sickle cell disease under medical care, not to general supplement use.
Muscle mass and strength
Preliminary or mixedA review of muscle supplements rated the evidence for glutamine as weak or scarce.
Supplements: Weak or scarce evidence for healthy people.
Gut lining and gut repair claims
Not enough evidenceGut and immunity claims for glutamine powders are common. A Cochrane review of growth hormone with or without glutamine in short bowel syndrome was inconclusive.
Supplements: We found no reliable human trials in healthy people; treat gut healing claims as unproven.
Recovery and immune function in healthy people
Not enough evidenceClaims that glutamine speeds recovery or protects immunity in healthy active people are not supported by sources we read.
Supplements: No sources read show a benefit in healthy people.
Connected topics
Open a group to see how each topic connects and how strong the evidence is.
Body systems (2)
- Kidney & UrinaryDocumented risk
A review reported glutamine can raise serum creatinine and cause kidney damage in diabetic kidney disease; no significant harm was seen in healthy athletes.
- Urinary SystemDocumented risk
A review reported glutamine can raise serum creatinine and cause kidney damage in diabetic kidney disease; no significant harm was seen in healthy athletes.
Body parts (1)
- KidneysDocumented risk
A review reported glutamine can raise serum creatinine and cause kidney damage in diabetic kidney disease; no significant harm was seen in healthy athletes.
Root causes (1)
- Nutrient DeficiencyDeficiency link
Glutamine can become deficient in stress states such as critical illness, trauma, infection, cancer and gut disorders. This is an acquired depletion, not a common dietary deficiency.
Biomarkers (1)
- CreatinineDocumented risk
Serum creatinine rose with glutamine in people with diabetic kidney disease in the studies reviewed.
Conditions & symptoms (2)
- Anemia, Sickle CellClinically supported
A prescription L-glutamine powder (FDA-approved 2017, ages 5 and over) was linked to fewer pain crises in a 48-week trial. It is a medical product used under supervision.
- Diabetic NephropathyDocumented risk
A review reported glutamine can cause glomerulosclerosis and higher serum creatinine in diabetic kidney disease. People with it should ask a clinician first.
Documented risks and interactions (1)
- Kidney caution in diabetic kidney disease. A review found no significant harm in healthy athletes, but reported glutamine can cause glomerulosclerosis and higher serum creatinine in diabetic nephropathy.
Most of the strong research on glutamine is about hospital care or one prescription use, not about powders bought for training or digestion. This page keeps those apart. For the nine essential amino acids see essential amino acids. For the hospital and gut questions in more detail see glutamine, gut health, immune function and critical illness.
How to read the evidence labels
We use these labels: established medical use (an approved treatment for one condition), mixed, insufficient evidence, and weak or scarce evidence (the wording used by the review cited). Where we looked and found nothing usable we write "Proper evidence not found" and say what we searched.Evidence by use
| Use | What the sources found | Label |
|---|---|---|
| Critically ill adults and major surgery (given by hospital teams) | A Cochrane review of 53 trials (4,671 people) found fewer hospital-acquired infections with glutamine (risk ratio 0.79). [3] Deaths did not differ clearly, and ICU stay was slightly longer. [3] A later large trial in 1,223 adults with organ failure found more deaths with glutamine. [4] | Mixed |
| Sickle cell disease | In a 48-week trial of 230 people aged 5 to 58, pharmaceutical-grade L-glutamine given twice daily by mouth was linked to fewer pain crises than placebo (median 3 versus 4). [5] The FDA approved a prescription L-glutamine oral powder for people aged 5 and over in 2017. [6] | Established medical use of a prescription product |
| Short bowel syndrome | A Cochrane review found the evidence inconclusive for growth hormone with or without glutamine. [7] | Insufficient evidence |
| Muscle mass and strength in healthy people | A review of muscle supplements rated glutamine as weak or scarce evidence. [8] | Weak or scarce evidence |
| Gut "healing", immunity, general recovery in healthy people | Proper evidence not found: we searched PubMed for human trials of glutamine in healthy people and found none we could rely on. | Insufficient evidence |
The sickle cell trial tested a pharmaceutical-grade product at a weight-based amount, in people with a specific diagnosis, under medical care. It was funded by Emmaus Medical. [5] It does not show that a store-bought powder helps healthy people. Nor does hospital feeding research apply to someone taking a scoop at home.
Amounts and official limits
Amounts in studies are study amounts, not advice. A published risk assessment found strong evidence of no adverse effects in healthy adults at supplemental glutamine intakes up to 14 g a day, which it called the "observed safe level"; much higher amounts had been tested without harm, but the data were not enough for a confident long-term conclusion. [9] A 2023 review noted that no national health agency has set a tolerable upper intake level for individual amino acids, and glutamine was not among the ten amino acids it proposed values for. [10] We found no official recommended intake for glutamine in the sources we read.Forms and labels
Supplements are usually L-glutamine powder or capsules, and glutamine can also appear inside protein or recovery blends. Check grams per serving so amounts are not doubled. See reading supplement labels. For recovery nutrition more broadly see protein for muscle, training and recovery.Frequently asked questions
Is glutamine an essential amino acid?
No. MedlinePlus lists it as nonessential and conditionally essential, meaning it is usually made by the body but may be needed in illness and stress. [1]
Does glutamine build muscle?
A review of muscle supplements rated the evidence for glutamine as weak or scarce. [8]
Is glutamine a medicine?
In the US, the FDA approved a prescription L-glutamine oral powder for sickle cell disease in people aged 5 and over. [6] That is a medical product used under supervision.
Is glutamine safe for the kidneys?
In healthy athletes, a review found no significant adverse effects, but it reported glutamine can cause kidney problems in diabetic kidney disease. [11]
How much glutamine has been tested without harm?
A risk assessment set an observed safe level of 14 g a day for healthy adults, and said higher amounts lacked enough long-term data. [9] No national upper limit has been set. [10]
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, medicines and who should ask first
- Kidneys and diabetes. A review found no significant harm in healthy athletes after short-term (20 to 30 g within a few hours) or two-week use, but reported that glutamine can cause glomerulosclerosis and a rise in serum creatinine in diabetic kidney disease. [11] People with kidney disease, or diabetes with kidney problems, should talk to their clinician first. See existing conditions.
- Sickle cell trial side effects. Low-grade nausea, chest pain not from the heart, fatigue and muscle or bone pain were reported more often with glutamine than placebo. [5]
- Liver disease, pregnancy, breastfeeding, children and older adults. Not described in the sources we read, so no claim is made. Ask a clinician or pharmacist.
- Medicines and surgery. Interactions are not described in the sources we read. See how interactions work and supplements before surgery.
- Product quality. Powders vary; see quality testing and certifications and sports certification and banned substances.
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.
- 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.
- Valenzuela PL et al. Supplements with purported effects on muscle mass and strength. Eur J 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.
- Elango R. Tolerable upper intake level for individual amino acids in humans: a narrative review of recent clinical studies. Adv Nutr 2023. 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.