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Last verified: 10 days ago

L-Glutamine

Also known as: Glutamine, Gln, L-Gln, 2-amino-4-carbamoylbutanoic acid

Evidence under review. — Not yet rated

Amino acid with some evidence for reducing oral mucositis severity during cancer treatment.

What the Science Says

L-Glutamine is a naturally occurring amino acid — one of the most abundant in the body. The strongest evidence from provided studies is for reducing the severity of radiation-induced oral mucositis (mouth sores) in head and neck cancer patients, where 5g oral doses helped lower pain, preserve body weight, and improve quality of life during radiotherapy. It has also been studied in combination with other nutrients before cardiac surgery, where it may help reduce pre-surgical inflammation markers.

What It Doesn't Do

Not proven to build muscle or speed gym recovery based on these studies. No evidence here it heals leaky gut on its own. The Alzheimer's prevention claim is purely theoretical — no clinical trial data supports it. Don't expect it to replace medical treatment for any condition.

Evidence-Based Benefits

Reduces severity of radiation-induced mouth sores and pain in head and neck cancer patients.

Moderate Evidence

Effective at: 5g daily oral suspension

Supporting studies (click to view on PubMed):

Helps prevent weight loss during radiotherapy in head and neck cancer patients.

Weak Evidence

Effective at: 5g daily

Supporting studies (click to view on PubMed):

May reduce pre-surgical inflammation markers when combined with HMB and arginine before cardiac surgery.

Weak Evidence

Effective at: 7000mg twice daily (in combination)

Supporting studies (click to view on PubMed):

Absorption & Bioavailability

Unknown from provided studies — oral forms were used in clinical trials but absorption data was not reported.

Red Flags to Watch For

  • Most studies used L-glutamine in combination with other ingredients (arginine, HMB, hyaluronic acid), making it impossible to isolate glutamine's individual effect
  • Cancer treatment studies were small (23–24 patients per group) — results may not generalize broadly
  • The cardiac surgery study used a multi-ingredient supplement; attributing benefits to glutamine alone is not valid
  • Theoretical Alzheimer's prevention claims circulating online have zero clinical trial support in the provided evidence

Products Containing L-Glutamine

See how L-Glutamine is used in these analyzed products:

Frequently Asked Questions

What does L-Glutamine do?

Amino acid with some evidence for reducing oral mucositis severity during cancer treatment.

What is the effective dose of L-Glutamine?

5-7g daily based on study doses

Is L-Glutamine safe?

Most studies used L-glutamine in combination with other ingredients (arginine, HMB, hyaluronic acid), making it impossible to isolate glutamine's individual effect

What doesn't L-Glutamine do?

Not proven to build muscle or speed gym recovery based on these studies.

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: 2026-06-01