Overview
Most abundant amino acid; primary fuel for enterocytes and immune cells.
- Beef
- Eggs
- Dairy
- Cabbage
- L-Glutamine
Forms & variants of L-Glutamine
Different chemical forms of L-Glutamine behave differently. Browse each form's mechanism, bioavailability, and best-use context.
Mechanism of action
Primary nitrogen donor; enterocyte and lymphocyte fuel.
- · Glutaminolysis
- · Glutathione synthesis
Effects on the body
Organ system effects
May support recovery in IBS-D and chemo-related mucositis.
Evidence-based benefits
Reduces IBS-D severity in post-infectious
Moderate evidenceReduces mucositis in chemotherapy
Moderate evidencePotential side effects
- · L-Glutamine is generally well-tolerated at evidence-based doses
- · Mild GI discomfort (nausea, loose stools, or bloating) possible at higher intakes
- · Headache or transient fatigue reported by a small fraction of users
- · Allergic or hypersensitivity reaction (rash, itching, swelling)
- · Sleep disturbance if taken late in the day
- · Discontinue and seek medical advice if symptoms are severe, persistent, or include difficulty breathing
Drug interactions
Safety & non-supplemental interactions
Educational summary — always confirm with your clinician or pharmacist before starting, stopping, or combining with prescription therapy.
- ·Autoimmune disease (theoretical immune activation)
- ·Immunosuppressants
Supplement interactions
- Vitamin D3 + K2Foundational immune modulation.
- ZincRequired cofactor for innate and adaptive immune function.
No specific avoidances listed.
Dosing & bioavailability
Where to buy
Affiliate links — we may earn a commission at no extra cost to you. Amazon code supplementsch-20 is auto-applied at checkout. We don't endorse specific brands; verify third-party testing (USP, NSF, Informed Sport) before purchase.
Third-party testedIndependently verified L-Glutamine — look for USP, NSF, or Informed Sport seals on the label for purity and dose accuracy.L-Glutamine third party tested NSF
CapsulesPre-measured L-Glutamine capsules — easiest for travel and consistent daily dosing without scoops or scales.L-Glutamine capsules
PowderBulk unflavored L-Glutamine powder — best cost-per-gram and flexible dosing for stacking or mixing into drinks.L-Glutamine powder unflavored
Best sellersMost-purchased L-Glutamine products on Amazon — a quick way to see what's reviewed widely before you commit.L-Glutamine best sellerScientific evidence9Show studiesHide studies
L-Glutamine: pharmacology, clinical evidence, and safety — narrative review
Examine.com Research Team
Curated narrative review of human and preclinical evidence for L-Glutamine, including mechanism, typical dosing, and safety considerations.
Best-supported outcome: Reduces IBS-D severity in post-infectious (evidence: moderate). Additional outcomes and limitations summarized in the full profile.
PubMed: L-Glutamine — Reduces IBS-D severity in post-infectious
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Live results for "L-Glutamine Reduces IBS-D severity in post-infectious" across the PubMed/MEDLINE peer-reviewed index.
Opens current human and preclinical literature matching L-Glutamine and "Reduces IBS-D severity in post-infectious". Filter by RCT, meta-analysis, or year on the results page.
PubMed: L-Glutamine — Reduces mucositis in chemotherapy
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Live results for "L-Glutamine Reduces mucositis in chemotherapy" across the PubMed/MEDLINE peer-reviewed index.
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PubMed: L-Glutamine — randomized controlled trial
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Live results for "L-Glutamine randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.
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PubMed: L-Glutamine — meta-analysis
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PubMed: L-Glutamine — pharmacokinetics
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PubMed: L-Glutamine — safety adverse events
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PubMed: L-Glutamine — dose response
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Live results for "L-Glutamine dose response" across the PubMed/MEDLINE peer-reviewed index.
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Google Scholar: L-Glutamine — clinical evidence
Live Scholar search
Cross-database citation index for L-Glutamine as it relates to "clinical evidence".
Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.