L-Glutamine
Research reviewed: Up until 03/2026
L-Glutamine is a dietary supplement with 12 published peer-reviewed studies involving 890 participants, researched for Gut Health, Immune Function, Muscle Recovery.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Gut Health
StrongImmune Function
StrongMuscle Recovery
StrongResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Gut Health
To evaluate the impact of glutamine supplementation on intestinal permeability in adults
Study Type
Systematic review and meta-analysis
Purpose
To evaluate the impact of glutamine supplementation on intestinal permeability in adults
Dose
Various
Participants
Multiple RCTs pooled
Duration
Various
Results
Glutamine supplementation significantly reduced gut permeability markers vs placebo in clinical settings.
How They Measured It
Lactulose/mannitol ratio, serum endotoxin, gut permeability
To assess oral L-glutamine supplementation for irritable bowel syndrome
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess oral L-glutamine supplementation for irritable bowel syndrome
Dose
15 g/day L-glutamine
Participants
106 post-infectious IBS patients
Duration
8 weeks
Results
Glutamine significantly reduced IBS-SSS scores by 50% and decreased gut permeability vs placebo.
How They Measured It
IBS symptom severity score (IBS-SSS), gut permeability, bowel frequency
To evaluate glutamine supplementation effect on gut permeability in critically ill patients
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate glutamine supplementation effect on gut permeability in critically ill patients
Dose
30 g/day intravenous glutamine
Participants
84 ICU patients
Duration
7 days
Results
Glutamine significantly maintained gut barrier integrity and reduced bacterial translocation vs placebo.
How They Measured It
Lactulose/mannitol ratio, bacterial translocation markers
To evaluate glutamine effect on radiation therapy-induced diarrhoea and gut damage
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate glutamine effect on radiation therapy-induced diarrhoea and gut damage
Dose
30 g/day L-glutamine
Participants
100 cancer patients undergoing radiotherapy
Duration
During radiotherapy
Results
Glutamine supplementation significantly reduced radiation-induced diarrhoea and gut mucositis.
How They Measured It
Stool frequency, gut permeability, intestinal damage markers
Immune Function
To assess glutamine supplementation on immune function in critically ill patients
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess glutamine supplementation on immune function in critically ill patients
Dose
0.5 g/kg/day glutamine
Participants
45 critically ill patients
Duration
10 days
Results
Glutamine significantly improved lymphocyte counts and NK cell activity; reduced nosocomial infections.
How They Measured It
Lymphocyte counts, NK cell activity, infection rates
To evaluate glutamine supplementation effect on immune outcomes in surgical patients
Study Type
Systematic review and meta-analysis
Purpose
To evaluate glutamine supplementation effect on immune outcomes in surgical patients
Dose
Various
Participants
Multiple trials pooled
Duration
Various
Results
Glutamine supplementation significantly reduced infection complications and improved immune cell function in surgery patients.
How They Measured It
Infection rates, lymphocyte function, hospital stay
To assess L-glutamine supplementation on salivary IgA and upper respiratory infections in athletes
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess L-glutamine supplementation on salivary IgA and upper respiratory infections in athletes
Dose
5 g post-exercise L-glutamine
Participants
151 endurance athletes post-marathon
Duration
7 days post-race
Results
Athletes supplementing glutamine had significantly lower URI incidence (19% vs 51% placebo) in the week post-marathon.
How They Measured It
Salivary IgA, URI incidence
To evaluate glutamine supplementation on neutrophil function in athletes
Study Type
Randomised, controlled trial
Purpose
To evaluate glutamine supplementation on neutrophil function in athletes
Dose
6 g/day glutamine
Participants
30 trained adults
Duration
14 days
Results
Glutamine maintained neutrophil function post-intensive exercise vs significant decline in placebo group.
How They Measured It
Neutrophil phagocytic capacity, respiratory burst
Muscle Recovery
To assess L-glutamine effect on muscle soreness and recovery after eccentric exercise
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess L-glutamine effect on muscle soreness and recovery after eccentric exercise
Dose
0.3 g/kg body weight glutamine
Participants
16 healthy adults
Duration
Post-eccentric exercise
Results
Glutamine significantly reduced muscle soreness and CK levels; improved torque recovery vs placebo.
How They Measured It
Muscle soreness VAS, CK levels, peak torque
To evaluate L-glutamine supplementation for plasma glutamine depletion in endurance athletes
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate L-glutamine supplementation for plasma glutamine depletion in endurance athletes
Dose
6 g/day during 6-day intensive training
Participants
25 endurance athletes
Duration
6 days
Results
Glutamine supplementation prevented the significant fall in plasma glutamine seen in placebo group during overtraining.
How They Measured It
Plasma glutamine levels, performance tests
To assess glutamine supplementation on body composition and strength in resistance-trained athletes
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess glutamine supplementation on body composition and strength in resistance-trained athletes
Dose
0.9 g/kg fat-free mass glutamine
Participants
31 resistance-trained athletes
Duration
6 weeks
Results
Glutamine did not significantly change body composition but significantly improved muscle strength and power.
How They Measured It
Lean body mass (DXA), strength (1RM), power output
To evaluate the effect of L-glutamine on muscle damage markers and recovery after exercise
Study Type
Systematic review and meta-analysis
Purpose
To evaluate the effect of L-glutamine on muscle damage markers and recovery after exercise
Dose
Various
Participants
Multiple RCTs pooled
Duration
Various
Results
L-glutamine supplementation significantly reduced exercise-induced muscle damage markers (SMD -0.58).
How They Measured It
CK, LDH, muscle soreness, recovery time
Frequently Asked Questions
Common questions about L-Glutamine research
There are currently 12 peer-reviewed studies on L-Glutamine (L-Glutamine), involving 890 total participants. Research covers Gut health, Immune function, Muscle recovery. The overall evidence strength is rated as Very Strong.
The evidence is currently rated as "Very Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (12 human studies), and reported outcomes.
L-Glutamine has been researched for: Gut health, Immune function, Muscle recovery. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 12 out of 12 studies are human trials. Human trials carry more weight in our evidence scoring system.
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