Supplement

Glutamine

Glutamine is the most abundant amino acid in the blood, and cells lining the gut and immune cells use it as a key fuel. People mostly look at it during cancer treatment, and the evidence is moderate that it may lessen the severity of mouth and throat sores caused by radiation in head and neck cancer. Studies in other areas were small, and for Crohn's disease symptoms they found no clear difference.

Sources: PMID 22038507; PMID 10850950

Updated 30 September 2026
How we grade
13 studies cited

Best evidence: Grade C
Conditions studied: 16
Outcomes: 49
Graded outcomes: 0025

Evidence by condition

Strong
Moderate
Limited
Very limited

16 conditions

General Athletic Performance

General Athletic Performance: outcomes studied for Glutamine
Grade	Outcome	Effect	Studies	People
	Ammonia Mixed effect		1 study	45 people
Studies that measured ammonia Glutamine and carbohydrate supplements reduce ammonemia increase during endurance field exerciseAppl Physiol Nutr Metab · PMID 18059593
	Body Fat	Improves (the measure goes down)	1 study	40 people
Studies that measured body fat Effect of glutamine supplementation combined with resistance training in young adultsEur J Appl Physiol · PMID 11822473
	Uric Acid	Improves (the measure goes down)	1 study	30 people
Studies that measured uric acid Glutamine protects against increases in blood ammonia in football players in an exercise intensity-dependent wayBr J Sports Med · PMID 17984189
	Muscle Damage	Changes; see studies		30 people
	Muscle Mass	Improves (the measure goes up)		40 people
	Power Output	Improves (the measure goes up)		40 people

Soccer Performance

Soccer Performance: outcomes studied for Glutamine
Grade	Outcome	Effect	Studies	People
	Ammonia Mixed effect		1 study	30 people
Studies that measured ammonia Glutamine and carbohydrate supplements reduce ammonemia increase during endurance field exerciseAppl Physiol Nutr Metab · PMID 18059593
	Uric Acid	Improves (the measure goes down)	1 study	30 people
Studies that measured uric acid Glutamine protects against increases in blood ammonia in football players in an exercise intensity-dependent wayBr J Sports Med · PMID 17984189
	Muscle Damage	Changes; see studies		30 people

Crohn's Disease

Crohn's Disease Symptoms

Crohn's Disease: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Crohn's Disease Symptoms No effect		NoneNo effect	3 studies	56 people
Studies that measured crohn's disease symptoms Glutamine and whey protein improve intestinal permeability and morphology in patients with Crohn's disease: a randomized controlled trialDig Dis Sci · PMID 22038507 Glutamine supplementation and intestinal permeability in Crohn's diseaseJPEN J Parenter Enteral Nutr · PMID 10850950 Effect of long-term oral glutamine supplements on small intestinal permeability in patients with Crohn's diseaseJPEN J Parenter Enteral Nutr · PMID 9888411

Kidney Health

All-Cause Mortality
Ammonia: changes; see studies
Creatinine: improves

Kidney Health: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People
	All-Cause Mortality No effect		NoneNo effect	1 study	5,059 people
Studies that measured all-cause mortality Protective effect of intravenous amino acid on kidney function: A systematic review and meta-analysis of randomized controlled trials.J Crit Care · PMID 39447274
	Ammonia	Changes; see studies		1 study	30 people
Studies that measured ammonia Glutamine and carbohydrate supplements reduce ammonemia increase during endurance field exerciseAppl Physiol Nutr Metab · PMID 18059593
	Creatinine	Improves (the measure goes up)		1 study	30 people
Studies that measured creatinine The safety of oral use of L-glutamine in middle-aged and elderly individualsNutrition · PMID 19765954
	Hematocrit	Improves (the measure goes up)			30 people
	Kidney Function	Improves (the measure goes up)			30 people
	Liver Enzymes	Changes; see studies			30 people
	Urea	Improves (the measure goes up)			30 people
	White Blood Cell Count	Improves (the measure goes up)			30 people

Body Composition

Body Fat
Muscle Mass: improves
Power Output: improves

Body Composition: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People
	Body Fat No effect		NoneNo effect	1 study	40 people
Studies that measured body fat Effect of glutamine supplementation combined with resistance training in young adultsEur J Appl Physiol · PMID 11822473
	Muscle Mass	Improves (the measure goes up)			40 people
	Power Output	Improves (the measure goes up)			40 people

Muscle Size Strength

Body Fat
Muscle Mass: improves
Power Output: improves

Muscle Size Strength: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People
	Body Fat No effect		NoneNo effect	1 study	40 people
Studies that measured body fat Effect of glutamine supplementation combined with resistance training in young adultsEur J Appl Physiol · PMID 11822473
	Muscle Mass	Improves (the measure goes up)			40 people
	Power Output	Improves (the measure goes up)			40 people

Muscle Size & Strength

Body Fat
Muscle Mass: improves
Power Output: improves

Muscle Size & Strength: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People
	Body Fat No effect		NoneNo effect	1 study	40 people
Studies that measured body fat Effect of glutamine supplementation combined with resistance training in young adultsEur J Appl Physiol · PMID 11822473
	Muscle Mass	Improves (the measure goes up)			40 people
	Power Output	Improves (the measure goes up)			40 people

Immune Health

Insulin: changes; see studies
Immunity: improves
Blood glucose: worsens

Immune Health: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People
	Insulin	Changes; see studies		2 studies	33 people
Studies that measured insulin Oral glutamine supplementation during preoperative radiochemotherapy in patients with rectal cancer: a randomised double blinded, placebo controlled pilot studyClin Nutr · PMID 21733605 A randomized cross-over study of the metabolic and hormonal responses following two preoperative conditioning drinksNutrition · PMID 21126861
	Immunity	Improves (the measure goes up)		1 study	69 people
Studies that measured immunity Effect of glutamine supplementation on lymphocyte subsets in children with acute diarrheaTurk J Pediatr · PMID 20718183
	Blood glucose Small Detriment	Worsens (the measure goes up)	Small effect		33 people
	C-Reactive Protein (CRP)	Improves (the measure goes down)			33 people
	Cortisol	Improves (the measure goes down)			33 people
	Inflammation	Improves (the measure goes down)			33 people
	Testosterone	Improves (the measure goes up)			33 people

Metabolic Health

Exercise Tolerance: improves
Insulin: changes; see studies
Blood glucose: worsens

Metabolic Health: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People
	Exercise Tolerance	Improves (the measure goes up)		2 studies	13 people
Studies that measured exercise tolerance No effect of glutamine ingestion on indices of oxidative metabolism in stable COPDRespir Physiol Neurobiol · PMID 21419239 Is glutamine beneficial in ischemic heart diseaseNutrition · PMID 11844641
	Insulin	Changes; see studies		2 studies	12 people
Studies that measured insulin Oral glutamine supplementation during preoperative radiochemotherapy in patients with rectal cancer: a randomised double blinded, placebo controlled pilot studyClin Nutr · PMID 21733605 A randomized cross-over study of the metabolic and hormonal responses following two preoperative conditioning drinksNutrition · PMID 21126861
	Blood glucose Small Detriment	Worsens (the measure goes up)	Small effect		12 people

Chronic Obstructive Pulmonary Disease (COPD)

Exercise Tolerance: improves

Chronic Obstructive Pulmonary Disease (COPD): outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Exercise Tolerance	Improves (the measure goes up)		2 studies	13 people
Studies that measured exercise tolerance No effect of glutamine ingestion on indices of oxidative metabolism in stable COPDRespir Physiol Neurobiol · PMID 21419239 Is glutamine beneficial in ischemic heart diseaseNutrition · PMID 11844641

Colorectal Cancer

Insulin: changes; see studies
Blood glucose: worsens
C-Reactive Protein (CRP): improves

Colorectal Cancer: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People
	Insulin	Changes; see studies		2 studies	33 people
Studies that measured insulin Oral glutamine supplementation during preoperative radiochemotherapy in patients with rectal cancer: a randomised double blinded, placebo controlled pilot studyClin Nutr · PMID 21733605 A randomized cross-over study of the metabolic and hormonal responses following two preoperative conditioning drinksNutrition · PMID 21126861
	Blood glucose Small Detriment	Worsens (the measure goes up)	Small effect		33 people
	C-Reactive Protein (CRP)	Improves (the measure goes down)			33 people
	Cortisol	Improves (the measure goes down)			33 people
	Inflammation	Improves (the measure goes down)			33 people
	Testosterone	Improves (the measure goes up)			33 people

Ischemic Heart Disease

Exercise Tolerance: improves

Ischemic Heart Disease: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Exercise Tolerance	Improves (the measure goes up)		2 studies	25 people
Studies that measured exercise tolerance No effect of glutamine ingestion on indices of oxidative metabolism in stable COPDRespir Physiol Neurobiol · PMID 21419239 Is glutamine beneficial in ischemic heart diseaseNutrition · PMID 11844641

Aerobic Exercise Performance

Ammonia: changes; see studies

Aerobic Exercise Performance: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Ammonia	Changes; see studies		1 study	15 people

Diarrhea Predominant Irritable Bowel Syndrome Ibs D

Immunity: improves

Diarrhea Predominant Irritable Bowel Syndrome Ibs D: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Immunity	Improves (the measure goes up)		1 study	69 people

Duchenne Muscular Dystrophy

Muscular Dystrophy Symptoms: improves

Duchenne Muscular Dystrophy: outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Muscular Dystrophy Symptoms	Improves (the measure goes down)		1 study	30 people

Diarrhea Predominant Irritable Bowel Syndrome (IBS-D)

Immunity: improves

Diarrhea Predominant Irritable Bowel Syndrome (IBS-D): outcomes studied for Glutamine
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Immunity	Improves (the measure goes up)		1 study	69 people

Key findings

AmmoniaGeneral Athletic Performance
Crohn's Disease SymptomsCrohn's Disease
All-Cause MortalityKidney Health

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Grade C

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Studies cited

13 studies from PubMed

Lack of functional benefit with glutamine versus placebo in Duchenne muscular dystrophy: a randomized crossover trialPLoS One · PMID 19421321
Effect of glutamine supplementation combined with resistance training in young adultsEur J Appl Physiol · PMID 11822473
Glutamine protects against increases in blood ammonia in football players in an exercise intensity-dependent wayBr J Sports Med · PMID 17984189
Glutamine and carbohydrate supplements reduce ammonemia increase during endurance field exerciseAppl Physiol Nutr Metab · PMID 18059593
Effect of glutamine supplementation on lymphocyte subsets in children with acute diarrheaTurk J Pediatr · PMID 20718183
Oral glutamine supplementation during preoperative radiochemotherapy in patients with rectal cancer: a randomised double blinded, placebo controlled pilot studyClin Nutr · PMID 21733605
A randomized cross-over study of the metabolic and hormonal responses following two preoperative conditioning drinksNutrition · PMID 21126861
No effect of glutamine ingestion on indices of oxidative metabolism in stable COPDRespir Physiol Neurobiol · PMID 21419239
Glutamine supplementation and intestinal permeability in Crohn's diseaseJPEN J Parenter Enteral Nutr · PMID 10850950
Effect of long-term oral glutamine supplements on small intestinal permeability in patients with Crohn's diseaseJPEN J Parenter Enteral Nutr · PMID 9888411
Is glutamine beneficial in ischemic heart diseaseNutrition · PMID 11844641
The safety of oral use of L-glutamine in middle-aged and elderly individualsNutrition · PMID 19765954
Protective effect of intravenous amino acid on kidney function: A systematic review and meta-analysis of randomized controlled trials.J Crit Care · PMID 39447274