Glutamine

amino acid
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Glutamine is a non-essential amino acid that the body synthesizes naturally, though it becomes conditionally essential during physiological stresses such as intense exercise, critical illness, or trauma. It is the most abundant amino acid in the bloodstream and is vital for protein synthesis, nitrogen transport, and maintaining the integrity of the intestinal lining. It fuels rapidly dividing cells, particularly immune cells and enterocytes, the cells lining the gut. In addition to its role in cellular metabolism, glutamine supports the immune system by supporting the growth and function of lymphocytes and macrophages. It is also critical for digestive health, helping repair and maintain the intestinal barrier, which can be compromised during stress or illness. Athletes often use it to support muscle protein synthesis and reduce soreness after strenuous physical activity. Glutamine acts as a precursor for other molecules, including the antioxidant glutathione and various amino acids. It also assists in maintaining acid-base balance and removing excess ammonia from the system. Because of these diverse functions, it is often supplemented to support immune health, athletic performance and recovery, and overall digestive well-being.

Natural sources
BeefChickenPorkFishEggsDairy products (milk, yogurt, cheese)SpinachParsleyCabbageBeetsBeansLentils

No public comparison lists found.

Optimal Dosage
Minimum5000 mg
Maximum10000 mg
Safety & Toxicity
4 safety notes
  • Individuals with liver disease, kidney disease, or Reye's syndrome should avoid glutamine supplementation unless advised by a healthcare professional.
  • Pregnant or breastfeeding women should consult a doctor before use.
  • Do not exceed recommended dosages.
  • Monitor for signs of allergic reaction, such as rash or difficulty breathing.
Goals
Gut Health
Gut Health
Impact
Highest effect
Typical dose:5–15 g

Glutamine is the primary energy source for enterocytes (cells lining the intestine). It plays a crucial role in maintaining tight junction integrity, preventing intestinal permeability (often called 'leaky gut'), and supporting tissue repair within the GI tract.

Focuses on
Gut LiningRegularityGut InflammationGut Flora
Most relevant for
People facing significant gastrointestinal stress from intense exercise, recovery from major surgery, or specific medical treatments like chemotherapy.

Potential benefits

  • Intestinal Barrier Support.Supplementation may help maintain the gut lining and reduce markers of intestinal permeability caused by intense physical stress, such as running in heat, or severe illness.
  • Diarrhea Management in Treatment.Evidence suggests glutamine may reduce the duration or risk of diarrhea in patients undergoing chemotherapy or recovering from colorectal surgery.
  • Support for Nutrient Absorption.In specific compromised states like severe trauma or chronic illness, it may support mucosal integrity to help improve intestinal nutrient absorption.

Limitations

  • General Wellness Uncertainty.There is no established benefit for improving daily digestive comfort or routine gut health in healthy individuals not experiencing acute physical stress.
  • Radiotherapy Efficacy.Systematic reviews indicate glutamine is generally ineffective at preventing gastrointestinal symptoms caused specifically by pelvic radiation therapy.
  • Marker and Symptom Mismatch.Improved laboratory markers of gut barrier function or microbial ratios do not always translate into a noticeable reduction in symptoms like bloating or pain.
Things to consider

High oral doses may cause mild side effects including nausea, belching, or abdominal discomfort.

Study evidence

37 studies

Glutamine may support the intestinal barrier or reduce digestive complications in some medical settings, but results vary by condition. Evidence does not establish a general digestive benefit in healthy people, and improvements in gut markers do not always translate into fewer symptoms.

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Liver & Detox
Liver & Detox
Impact
High effect
Typical dose:1000–5000 mg

Glutamine is the primary fuel for enterocytes, the cells lining the gut. A strong gut barrier prevents bacterial endotoxins like LPS from entering the bloodstream and traveling to the liver, thereby decreasing hepatic inflammation and the overall detoxification burden.

Focuses on
Liver ProtectionToxin ProcessingElimination
Most relevant for
Individuals undergoing liver-related surgery or receiving specialized medical nutrition under clinical supervision.

Potential benefits

  • Supportive liver function.Unconfirmed. Research in patients undergoing liver surgery or bone marrow transplants suggests that glutamine may help stabilize liver enzymes and maintain protein levels during the recovery process.
  • Ammonia metabolism role.Unconfirmed. Glutamine is a key participant in the conversion of ammonia for excretion, which is a critical component of biological detoxification, particularly in the brain and liver.
  • Gut barrier protection.Unconfirmed. As a primary fuel for intestinal cells, glutamine may support the gut lining, potentially reducing the amount of gut-derived toxins that reach the liver for processing.

Limitations

  • Clinical setting constraints.Most supportive evidence involves intravenous administration or specialized medical nutrition for surgical patients, which may not apply to standard oral supplementation in healthy people.
  • Risk in severe liver failure.In conditions like hepatic encephalopathy, the accumulation of glutamine in the brain can contribute to cellular swelling and neurological complications.
  • Potential for liver enzyme elevation.Some studies involving intravenous glutamine have reported reversible increases in liver enzymes, suggesting that high doses may occasionally stress the liver.
Things to consider

Use with caution if you have severe liver impairment or a history of hepatic encephalopathy, as glutamine can affect brain ammonia levels. Reversible liver enzyme elevations have been observed in some clinical settings.

Study evidence

8 studies

Glutamine participates in ammonia metabolism, but the supplied research does not establish a general detoxification benefit from oral supplements. Favorable findings largely concern specialized medical nutrition and liver-related care, and liver enzyme elevations have occurred in some intravenous nutrition settings.

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Immunity
Immunity
Impact
Moderate effect
Typical dose:2–10 g

During illness or stress, immune cells like lymphocytes and macrophages have a high demand for glutamine as their preferred energy source. Supplementation supports their optimal function and proliferation. It also strengthens the gut lining, preventing pathogens from entering the bloodstream.

Focuses on
Immune NutrientsSeasonal DefenseImmune Balance
Most relevant for
Patients recovering from major surgery, severe burns, or critical illness who require specialized nutritional support.

Potential benefits

  • Support for Immune Cell Energy.Glutamine serves as a primary fuel source for lymphocytes and macrophages, and supplementation may help maintain cellular immune function during periods of severe metabolic stress like major surgery or burns.
  • Reduced Risk of Clinical Infections.Clinical meta-analyses indicate that glutamine-enriched nutrition can significantly decrease the incidence of infectious complications in patients undergoing colorectal surgery or those with severe pancreatitis.
  • Enhanced Antibody Production.In specific clinical populations, supplementation has been shown to increase levels of immunoglobulins like IgA and IgG, which are essential components of the body's humoral immune defense.

Limitations

  • Limited Benefit for Athletes.While intense exercise depletes circulating glutamine, studies consistently show that supplementing does not prevent the temporary immune suppression or changes in immune cell function that follow strenuous activity.
  • Clinical vs. General Use.Most evidence for immune support involves intravenous or tube-fed administration for severely ill patients; there is no established proof that oral supplements improve everyday immunity in healthy individuals.
  • Inconsistent Outcomes in Critical Care.Research in intensive care settings has found mixed results, with some trials showing no significant reduction in ventilator-associated pneumonia or overall mortality despite improvements in nutritional markers.
Things to consider

Mild gastrointestinal symptoms such as nausea, diarrhea, or constipation have been reported in some clinical trials.

Study evidence

36 studies

Glutamine supports immune-cell function, and supplementation may reduce infections in some surgical or severely ill patients receiving specialized nutrition. These clinical findings do not establish that ordinary oral Glutamine improves everyday immunity, and evidence for protecting athletes from exercise-related immune changes is unconvincing.

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Studies

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Interactions

Positive Interactions

Creatine
May synergistically enhance muscle recovery, performance, and hydration when taken together.
Leucine
Supports muscle protein synthesis and recovery; glutamine complements this by aiding cellular hydration and immune function.
Isoleucine
Works with glutamine to support muscle recovery and reduce muscle protein breakdown, particularly after intense exercise.
Valine
Combined with glutamine, it contributes to improved muscle repair and reduced fatigue during and after strenuous physical activity.
Vitamin C
Both support immune function; Vitamin C as an antioxidant and glutamine as fuel for immune cells.
Zinc
Essential for immune cell function, which glutamine also supports, potentially leading to enhanced immune response.
Gluthathione
Glutamine is a key precursor in the synthesis of glutathione, the body's master antioxidant, thereby supporting antioxidant defense.
Cysteine
As one of the three amino acids needed to form glutathione, cysteine works with glutamine to support the body's antioxidant capacity.
Glycine
Another building block of glutathione, glycine collaborates with glutamine to facilitate the production of this crucial antioxidant.
Glutamic Acid
Glutamine can be converted to glutamic acid and vice versa; both play roles in brain function and energy metabolism.

Negative Interactions

Caffeine
While not a direct negative interaction, high doses of caffeine can sometimes cause digestive upset, which might be exacerbated by very high doses of glutamine in sensitive individuals, though research is limited.
Sources

Up to five highest-ranked published examples per goal. Study counts and charts include all published studies for the connection.

  1. Effect of perioperative glutamine-enriched nutritional support on patients with colorectal cancer: A systematic review and meta-analysis.
    Huang Y; Yang XZ; Qin SH; Zhang T; Xie M; Wang JW · World journal of gastrointestinal surgery · 2026
    Meta-analysis1,643 participants27 studies pooledGut HealthImmunity
  2. Glutamine prevents diarrhea in colorectal cancer patients undergoing chemotherapy or chemoradiotherapy: a meta-analysis.
    Chen L; Wang D; Meng C; Sun H; Li R; Miao G; Liu P · BMC gastroenterology · 2025
    Meta-analysis311 participants5 studies pooledGut Health
  3. Glutamine supplementation reduces markers of intestinal permeability during running in the heat in a dose-dependent manner.
    Pugh JN; Sage S; Hutson M; Doran DA; Fleming SC; Highton J; Morton JP; Close GL · European journal of applied physiology · 2018
    Randomized trial10 participantsGut Health
  4. Effect of glutamine supplementation on diarrhea, interleukin-8 and secretory immunoglobulin A in children with acute diarrhea.
    Yalçin SS; Yurdakök K; Tezcan I; Oner L · Journal of pediatric gastroenterology and nutrition · 2004
    Randomized trial128 participantsGut Health
  5. Improvement of intestinal permeability with alanyl-glutamine in HIV patients: a randomized, double blinded, placebo-controlled clinical trial.
    Leite RD; Lima NL; Leite CA; Farhat CK; Guerrant RL; Lima AA · Arquivos de gastroenterologia · 2013
    Randomized trial46 participantsGut Health
  6. Efficacy of glutamine supplementation in postoperative patients undergoing hepatic surgery: a systematic review and meta-analysis of randomized controlled trials.
    Meng X; Zhang M; Wang X · Clinics (Sao Paulo, Brazil) · 2026
    Meta-analysis1,198 participants18 studies pooledLiver & Detox
  7. Glutamine supplementation in preterm infants receiving parenteral nutrition leads to an early improvement in liver function.
    Wang Y; Cai W; Tao YX; Tang QY; Feng Y; Wu J · Asia Pacific journal of clinical nutrition · 2014
    Randomized trial30 participantsLiver & Detox
  8. Parenteral glutamine protects hepatic function during bone marrow transplantation.
    Brown SA; Goringe A; Fegan C; Davies SV; Giddings J; Whittaker JA; Burnett AK; Poynton CH · Bone marrow transplantation · 1998
    Randomized trial34 participantsLiver & Detox
  9. Protective effect of parenteral glutamine supplementation on hepatic function in very low birth weight infants.
    Wang Y; Tao YX; Cai W; Tang QY; Feng Y; Wu J · Clinical nutrition (Edinburgh, Scotland) · 2010
    Randomized trial30 participantsLiver & Detox
  10. A multistrain probiotic increases the serum glutamine/glutamate ratio in patients with cirrhosis: a metabolomic analysis.
    Laghi L; Román E; Lan Q; Nieto JC; Canalda-Baltrons A; Poca M; Sánchez-Rodríguez MB; Clària J; Alvarado E; Cuyàs B; Sánchez E; Vidal S; Guarner C; Escorsell À; Manichanh C; Soriano G · Hepatology communications · 2023
    Randomized trial32 participantsLiver & Detox
  11. Meta-analysis of Glutamine on Immune Function and Post-Operative Complications of Patients With Colorectal Cancer.
    Yang T; Yan X; Cao Y; Bao T; Li G; Gu S; Xiong K; Xiao T · Frontiers in nutrition · 2021
    Meta-analysis2,201 participants31 studies pooledImmunity
  12. Efficacy of Glutamine in Treating Severe Acute Pancreatitis: A Systematic Review and Meta-Analysis.
    Dong S; Zhao Z; Li X; Chen Z; Jiang W; Zhou W · Frontiers in nutrition · 2023
    Meta-analysis1,201 participants30 studies pooledImmunity
  13. Decreased mortality and infectious morbidity in adult burn patients given enteral glutamine supplements: a prospective, controlled, randomized clinical trial.
    Garrel D; Patenaude J; Nedelec B; Samson L; Dorais J; Champoux J; D'Elia M; Bernier J · Critical care medicine · 2003
    Randomized trial45 participantsImmunity
  14. Glutamine administration reduces Gram-negative bacteremia in severely burned patients: a prospective, randomized, double-blind trial versus isonitrogenous control.
    Wischmeyer PE; Lynch J; Liedel J; Wolfson R; Riehm J; Gottlieb L; Kahana M · Critical care medicine · 2001
    Randomized trial26 participantsImmunity