Compound or practice · Supplement
L-Glutamine
The gut's favorite fuel — genuinely useful in clinical catabolic states, largely wasted money for healthy lifters.
- Overall grade
- Grade C
- Last revised
- 2
- graded outcomes
- 0
- references listed
A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.
1 at grade C · 1 at grade D — 2 graded rows
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Gut barrier (clinical)Evidence grade C
In catabolic states
Moderatemixed
- Muscle growth (healthy)Evidence grade D
No benefit over protein
Trivialhigh
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
- Thin evidence: Gut barrier (clinical) (grade C); Muscle growth (healthy) (grade D).
The evidence in words
What it is
Glutamine is the most abundant amino acid in blood and a primary fuel for intestinal and immune cells. It becomes 'conditionally essential' during severe stress (burns, surgery, critical illness) when demand outstrips supply.
How it works
It fuels rapidly-dividing gut and immune cells and supports intestinal barrier integrity. In health, the body makes plenty, so extra supplementation has little to act on.
What the evidence shows
Real benefits exist in clinical catabolic states and possibly in gut-barrier conditions. In healthy, well-fed athletes, it does not meaningfully improve muscle growth, strength, or immunity despite decades of marketing. Endurance 'leaky gut' and immune claims are weak.
How to use it
Not needed for healthy trainees. Clinical and gut-health uses (5–15 g/day) belong under guidance.
Safety & interactions
Very safe at supplemental doses.
Bottom line
Skip it if you're a healthy lifter — protein intake already covers you. It's a clinical-nutrition tool, not a physique supplement.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Clinical/gut
- 5–15 g/day, under guidance.
Related reading
Entries that share this one's tags or conditions.
- L-Glutamine for Gut barrier (clinical)Evidence grade C — In catabolic statesEvidence grade C
- L-Glutamine for Muscle growth (healthy)Evidence grade D — No benefit over proteinEvidence grade D
- L-Glutamine: dosage and how to take it5–15 g/day, under guidance.Evidence grade C
- L-Glutamine: side effects, safety & interactionsVery safe at supplemental doses.Evidence grade C
Sources
This entry lists no references of its own.
Last revised . A grade is this entry's reading of the evidence, not medical advice.