L-Glutamine
Also known as: Glutamine, Gln, L-Gln, 2-amino-4-carbamoylbutanoic acid
Effective Dosage
5,000–14,000 mg daily depending on condition (clinical use); No established general wellness dose
What the Science Says
L-Glutamine is a naturally occurring amino acid — the most abundant in the body — that plays a key role in immune function, tissue repair, and cellular energy. Clinical trials show it can meaningfully reduce the severity of radiation-induced mouth sores (oral mucositis) in cancer patients, helping preserve body weight and quality of life during treatment. In sickle cell disease, adding L-glutamine to standard hydroxyurea therapy significantly reduced painful crises, hospitalizations, and acute chest syndrome episodes compared to hydroxyurea alone, likely by improving the body's antioxidant defenses.
What It Doesn't Do
Won't build muscle on its own — the cardiac surgery studies used it in a multi-ingredient combo, so you can't credit glutamine alone. No evidence it boosts athletic performance or speeds gym recovery in healthy people. The Alzheimer's prevention and antidepressant uses described in some papers are untested hypotheses, not proven treatments. Don't expect gut-healing miracles — the gut health claims popular in supplement marketing aren't directly supported by the studies reviewed here.
Evidence-Based Benefits
L-Glutamine is an amino acid that plays a crucial role in protein synthesis and is important for gut health and immune function. It has been shown to help reduce muscle soreness and improve recovery after intense exercise, making it popular among athletes.
Strong EvidenceEffective at: 5-10 g daily
Source: auto-research
Absorption & Bioavailability
Unknown from provided studies — oral forms were used across trials with apparent clinical effect, but no pharmacokinetic data was reported in the provided abstracts.
Red Flags to Watch For
- Most positive findings come from specific medical populations (cancer patients, sickle cell disease) — benefits may not translate to healthy adults
- Cardiac surgery studies used L-glutamine in combination with HMB and L-arginine, making it impossible to isolate glutamine's individual contribution
- Alzheimer's prevention and antidepressant uses cited in provided papers are speculative hypotheses with no clinical trial data
- High doses used in clinical trials (7,000–14,000 mg/day) far exceed amounts in most retail supplements — check label doses carefully
- L-glutamine is FDA-approved for sickle cell disease (Endari) — using unregulated supplements as a substitute for a medical condition is risky
Products Containing L-Glutamine
See how L-Glutamine is used in these analyzed products:
Research Sources
- PubMed
- NIH DSLD
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-04-06