amino acid Amino Acids Oral

L-Glutamine

A conditionally essential amino acid that serves as a primary fuel source for gut and immune cells, supporting intestinal barrier function and immune response, especially during metabolic stress.

Sci.(2S)-2,5-diamino-5-oxopentanoic acid Glutamine L-Glutamic acid 5-amide
3 forms
Oral

About L-Glutamine

L-Glutamine is a conditionally essential amino acid that plays a crucial role in various physiological processes, particularly during metabolic stress, illness, or intense exercise. It is the most abundant free amino acid in human blood and muscle tissue, serving as a primary fuel source for rapidly dividing cells such as enterocytes and immune cells. L-Glutamine is vital for maintaining intestinal barrier integrity and supporting immune function, and it acts as a precursor for the synthesis of glutathione, nucleotides, and other amino acids. While marketed for gut health, immune support, and exercise recovery, evidence for its benefits in healthy individuals is mixed, with stronger support for its use in clinical settings like critical illness and trauma.

Official resources

Fact sheets from the NIH Office of Dietary Supplements related to this ingredient group.

At a glance

Suggested daily

No established RDA. Typical dietary intake is 3-6 grams per day from protein-rich foods. Supplemental doses in studies range from 5-30+ grams daily, often divided.

Max safe daily

No established UL. Short-term supplementation up to 0.9 g/kg body weight appears safe, but long-term safety data is limited. High doses may cause gastrointestinal discomfort.

Approval status

supplement

Compare All Forms

3 forms

Compare supplement forms of L-Glutamine by absorption quality and what your body actually gets from each:

High Moderate Low
Form Absorption Steps to absorb Notes Action
Free-form L-Glutamine Powder

Conditionally essential amino acid important for gut and imm...

  • UNII: 0RH81L854J
  • CAS: 56-85-9
  • Label category: synthetic
 — — — View →
L-Alanyl-L-Glutamine

Stable, bioavailable form of glutamine; supports gut health,...

  • UNII: 8W9VJ8438S
  • CAS: 39537-23-0
  • Label category: synthetic
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N-Acetyl-L-Glutamine

Enhanced stability & bioavailability form of glutamine.

  • UNII: V81Y9Q9F1J
  • CAS: 2490-97-3
  • Label category: synthetic
 — — — View →

Also appears on labels as

Additional names seen on supplement labels for forms of this ingredient (beyond the main aliases above).

Acetylglutamine, AG, Ala-Gln, Alanylglutamine, Glutamic acid 5-amide, L-Glutamine, Levoglutamide, N(2)-L-Alanyl-L-glutamine, N-Acetylglutamine, N-Acetyl Glutamine

Type: Amino Acids

Building blocks of proteins. Essential amino acids must be obtained from diet, while non-essential can be synthesized by the body.

Absorption: Amino acids are generally well-absorbed. Some forms (like citrulline) are more effective than others (like arginine).

Interactions: Generally safe but high doses can cause digestive issues. Some amino acids can affect neurotransmitter levels.

Watch out for

Possible interactions or cautions — talk to a healthcare provider if unsure.

  • Anticonvulsants (e.g., phenobarbital, primidone) - theoretical risk of reduced efficacy
  • Lactulose - may interfere with diagnostic tests for intestinal permeability

Potential Benefits

Benefits associated with L-Glutamine forms:

Immune System Support Gut Mucosal Support Muscle Recovery Support Nitrogen & Precursor Donor Gut Health Recovery

And 7 more benefits...

Potential Side Effects

Side effects associated with L-Glutamine forms:

Gastrointestinal Discomfort How serious: low Potential Metabolic Load in Certain Conditions How serious: medium None How serious: None Potential Risk in Certain Medical Conditions How serious: medium Potential for Nitrogen Load How serious: medium Potential for Neuroexcitation How serious: low

What does the research say?

Evidence for L-Glutamine's benefits in healthy individuals is mixed, but it shows stronger support in clinical settings such as critical illness, trauma, and chemotherapy-induced mucositis.