What do the states mean?+
- Solid: well studied, and it works.
- Half-there: the science is still forming.
- A ghost: almost no real studies.
- Hollow: well studied, and it does not work.
- A cord: the pair itself has been tested together.
- Air: nobody has ever tested this pair.
The full scoring method: How we score
L-glutamine benefits: where the science stands
For gut and digestion: yes.
Gut and digestion are what most people take L-glutamine for, and the strongest evidence says it helps (a combined review covering 5 trials, plus a trial of 106 people). As of August 2026, the verdicts on this page rest on evidence from 9 trials, drawn from the strongest research among the 2,029 papers on PubMed that mention L-glutamine. Every claim is checked below.
2,029 papers on PubMed · evidence from 9 trials
Claim by claim
- Gut and digestionWell studied, and it works. The biggest review covered 5 trials.
- Immunity and coldsAlmost no real studies. What exists leans positive.
Pairs people ask about
The three sources we read
- 2019Randomized trial · 106 people · large benefit for gut and digestionsource
- 2024Randomized trial · 21 people · moderate benefit for immunity and coldssource
- 2025Meta-analysis · pools 5 trials, 311 people · moderate benefit for gut and digestionsource
Chosen as the strongest evidence out of 2,029 papers on PubMed. Every row links to its paper.
Fair questions
Does L-glutamine work?+
For gut and digestion, yes. The biggest review covered 5 trials.
Is L-glutamine safe?+
No caution is recorded on this page. That is not a safety guarantee; the studies we read were not safety trials.
Why only 3 sources, when PubMed lists 2,029?+
The 2,029 is every paper that mentions L-glutamine in any way: animal studies, blood measurements, papers where it is a side note. The strongest sources are combined reviews, and each one already gathers every trial its authors could find. Our 3 cover 9 trials between them, and every one is linked above. Both counts are measured, not estimated.