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Lgn9.0
L-Glutamine Research
Likely helpsHigh safety
16 peer-reviewed studies
What the evidence says
Likely helps
L-Glutamine appears to help in 3 of 3 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 1999–2025 with a typical study size of 46 participants.
Based on 16 studies · 2 meta-analyses · 7 RCTs · 3,072 total participants
Confidence
High
What the studies found
3helped· 13 more without graded effect data
By outcome
Sickle cell disease
Mostly mechanism / observational3 studies
Immune supportSupports immune cell function during stress · 2-4 weeks
Mostly mechanism / observational3 studies
RecoveryMay reduce muscle soreness after intense training · 1-2 weeks
Mostly mechanism / observational3 studies
Therapeutic & clinical
Too few graded studies2 studies
Digestive healthImproved gut lining repair and reduced intestinal permeability within 4-8 weeks · 4-8 weeks
2Pain crises and hospital daysSystematic ReviewCited 5×n=97 · small study2025
A pivotal phase III study of l-glutamine showed that patients treated with l-glutamine had a 25 % reduction in pain crises and 33 % fewer hospital days compared to placebo. l-glutamine was generall...
Yassin M et al. · Blood reviews (2025)
Large benefit
← WorseNo effectBetter →
A pivotal phase III study of l-glutamine showed that patients treated with l-glutamine had a 25 % reduction in pain crises and 33 % fewer hospital days compared to placebo. l-glutamine was generally well tolerated with minimal side effects.
In the SUSTAIN study, a 5-mg/kg dose of crizanlizumab reduced the occurrence of vaso-occlusive crises (VOCs) and hospitalizations by 45 % and 41 %, respectively.
The high discontinuation rate and results of the STAND trial led to a significant decrease in the use of crizanlizumab.
3Peripheral blood metabolites in major depressive disorderMeta-AnalysisCited 171×n=46 · small study2021
This meta-analysis examined the effects of Acetyl-L-Carnitine.
Pu J et al. · Molecular psychiatry (2021)
Pathway and network analyses revealed altered amino acid metabolism and lipid metabolism, especially for the tryptophan-kynurenine pathway and fatty acid metabolism, in the peripheral system of MDD patients.
Our findings may facilitate biomarker development and the elucidation of the molecular mechanisms that underly MDD.
5Interleukin-6 expression and myalgia reductionSystematic ReviewCited 6×2022
According the scientific literature nutraceutical therapy associated with dexamethasone can reduce the expression of Interlukina-6(IL-6) and myalgia due to COVID-19.
Ripani U et al. · Medical archives (Sarajevo, Bosnia and Herzegovina) (2022)
According the scientific literature nutraceutical therapy associated with dexamethasone can reduce the expression of Interlukina-6(IL-6) and myalgia due to COVID-19.
6Muscle atrophy and functional mobility recoverySystematic ReviewCited 41×2018
Optimizing nutritional status pre-operatively may help manage the surgical stress response, with a particular benefit for undernourished, frail, or elderly individuals.
Burgess LC et al. · Nutrients (2018)
Amino acid supplementation is reported to reduce muscle atrophy and accelerate return of functional mobility.
One paper reported a suppressive effect of beta-hydroxy beta-methylbutyrate, L-arginine, and L-glutamine supplementation on muscle strength loss following TKR.
There is limited evidence for nutritional supplementation in THR and TKR pathways; however, the low risk profile and potential benefits to adjunctive treatment methods, such as exercise programs, suggest nutritional supplements may have a role.
7Safety and tolerabilityRCTCited 1×n=40 · small study2024
Our results indicate the product was well-tolerated at all dosing levels and no significant adverse changes occurred in any of the test parameters compared to the placebo group, indicating relative safety of ingestion over a 4-week treatment period, at the volumes used, and outside the context of physical stress.
8Pain crises over 48 weeksRCTCited 431×n=230 · medium study2018
Among children and adults with sickle cell anemia, the median number of pain crises over 48 weeks was lower among those who received oral therapy with l-glutamine, administered alone or with hydroxyurea, than among those who received placebo, with or without hydroxyurea. (Funded by Emmaus Medical; ClinicalTrials.gov number, NCT01179217 .).
Niihara Y et al. · The New England journal of medicine (2018)
Noticeable benefit
← WorseNo effectBetter →
Likely real
A total of 230 patients (age range, 5 to 58 years; 53.9% female) were randomly assigned, in a 2:1 ratio, to receive l-glutamine (152 patients) or placebo (78 patients).
The patients in the l-glutamine group had significantly fewer pain crises than those in the placebo group (P=0.005), with a median of 3.0 in the l-glutamine group and 4.0 in the placebo group.
Fewer hospitalizations occurred in the l-glutamine group than in the placebo group (P=0.005), with a median of 2.0 in the l-glutamine group and 3.0 in the placebo group.
9Mucosal immunity and upper respiratory tract infectionsRCTCited 7×n=21 · very small study2024
Three-week supplementation of L-glutamine after intensive training enhanced the mucosal immunity, improved hormonal status and reduced the rate of URTI of combat-sport athletes while feelings of well-being were also enhanced.
Lu TL et al. · Journal of the International Society of Sports Nutrition (2024)
Supplementation of L-glutamine significantly enhanced the concentrations of IgA and NO in saliva; additionally, the incidence of URTI was significantly reduced.
Regarding hormones, T concentration was significantly decreased in the PLA group, whereas C concentration was significantly increased, resulting in a significant decrease of T/C ratio.
In contrast, the GLU group showed a significant increase of T/C ratio, while the mood scores of the Hooper's index questionnaire were higher in the PLA group.
There was a decreasing trend in the number, severity, and hospitalization of VOC and a significantly lower cumulative number of VOCs and hospitalizations in the glutamine group than in SOC (p = 0.008, p < 0.001 respectively).
Time-averaged mean maximum velocity for the glutamine group had a marginal increase in both middle cerebral arteries, all values remained normal within a normal range, and in both internal carotid arteries, values increased from abnormally low to normal ranges at week 24.
Glutamine reduced the number of VOCs and severity and may have a potentially favorable impact on the cerebral arterial flow velocities.
It was concluded that the neurotransmitter-precursor-supplement intervention is effective in alleviating the withdrawal and mood symptoms and it may become a supplementary method for patients' recovery from heroin addiction.
Chen D et al. · Journal of Huazhong University of Science and Technology. Medical sciences = Hua zhong ke ji da xue xue bao. Yi xue Ying De wen ban = Huazhong keji daxue xuebao. Yixue Yingdewen ban (2012)
The results showed that the insomnia and withdrawal scores were significantly improved over time in participants in the intervention group as compared with those in the control group.
The sleep status and the withdrawal symptoms were observed daily throughout the study, and the mood states were monitored pre- and post-intervention.
A greater reduction in tension-anxiety, depression-dejection, anger-hostility, fatigue-inertia and total mood disturbance, and a greater increase in their vigor-activity symptoms were found at day 6 in the intervention group than in the control group (all P<0.05).
13Safety of L-glutamine supplementationRCTCited 24×n=30 · small study2010
Increases in serum urea nitrogen and creatinine and decrease in eGFR are probably due to difficulties by older kidneys in metabolizing the supplemented protein sources.
Galera SC et al. · Nutrition (Burbank, Los Angeles County, Calif.) (2010)
Noticeable benefit
← WorseNo effectBetter →
There were statistically but not clinically significant increases in plasma urea nitrogen and creatinine concentrations.
There was no significant decrease in eGFR during calcium caseinate supplementation (-2.9%).
The eGFR decreased significantly after L-Gln supplementation (-13.3%) but well below the 25% limit for biologic significance.