L-glutamine

Is L-glutamine FDA-approved?

Sold without a prescription. Supplements are not reviewed by the FDA before sale, so third-party testing matters. Sold as a dietary supplement; a separate prescription product is FDA-approved for sickle cell disease.

As of September 23, 2026.

How does L-glutamine work?

What does the evidence say about L-glutamine?

A 2024 meta-analysis found it may reduce gut permeability in some clinical settings; evidence for healthy people and for exercise recovery is weak.

What do clinicians say about L-glutamine?

Glutamine has a real prescription use in sickle cell disease. Evidence for gut health and exercise in healthy people is weak.

• FDA approved Endari in 2017 for people 5 and older with sickle cell disease, after a 48-week trial showed fewer pain crises and hospitalizations.

  FDA (July 2017): FDA approves new treatment for sickle cell disease

• A 2024 meta-analysis found no significant overall effect of glutamine on intestinal permeability.

  Glutamine supplementation and intestinal permeability: meta-analysis (Amino Acids 2024)

• NIH's Office of Dietary Supplements says glutamine has no effect or only a small benefit for strength training, with little evidence for performance.

  NIH ODS: Dietary supplements for exercise and athletic performance (consumer)

• A 2024 meta-analysis found enteral glutamine is unlikely to help critically ill adults beyond a modestly shorter hospital stay.

  Enteral glutamine in critically ill adults: meta-analysis (Clin Nutr 2024)

Summaries of published guidelines, drug labels, regulators and reviews, each attributed to its source. DiscoverMedica does not employ clinicians.

Is L-glutamine right for you, and who should avoid it?

Only a licensed clinician who knows your history can decide whether it is right for you.

What are the risks and side effects of L-glutamine?

• Generally well tolerated; bloating or nausea can occur.
• People with serious liver disease or a history of hepatic encephalopathy should avoid it without medical advice.
• People being treated for cancer should ask their oncologist first.

What should you ask a clinician about L-glutamine?

• What is behind my gut symptoms, and is glutamine a sensible step?
• Is it safe with my liver health and current treatments?

These save with the compound when you add it to My Journal, so they’re on the printout for your visit.

How do people buy L-glutamine?

1. 1

   No prescription is needed. Supplement brands and retailers sell it online and in stores.

2. 2

   Check with a clinician or pharmacist first if you take prescription medication or have a chronic condition.

3. 3

   Choose a product with independent testing, such as NSF Certified for Sport or USP Verified, because FDA does not check supplements before they are sold.

4. 4

   Endari, the prescription form for sickle cell disease, comes through your hematology team.

Where can I get L-glutamine?

10 providers list L-glutamine on DiscoverMedica, lowest listed price first.

† Prices as listed by the provider when we checked; they change.

L-glutamine: questions, answered

Sources

• Glutamine supplementation and gut permeability in adults: meta-analysis (2024)
• PubChem: L-glutamine (CID 5961)

Also checked for this guide

• FDA (July 2017): FDA approves new treatment for sickle cell disease
• FDA label: Endari (L-glutamine oral powder)
• Enteral glutamine in critically ill adults: meta-analysis (Clin Nutr 2024)
• NIH ODS: Dietary supplements for exercise and athletic performance (consumer)
• Thorne: Home and testing

Guide reviewed September 23, 2026.

Educational information only, not medical advice. It does not replace a conversation with a licensed clinician.