Glutamine

Also known as: L-glutamine, Gln

Grade B — Moderate Evidenceamino acidgutrecovery
5–10 gMorning and post-workout. Can take on empty stomach or with food.

L-Glutamine is the most abundant amino acid in the body, serving as a primary fuel source for immune cells and intestinal epithelial cells. It plays a critical role in gut barrier integrity, and supplementation (5-20g/day) has shown benefits for reducing intestinal permeability ("leaky gut"), supporting immune function during intense exercise, and aiding recovery from critical illness. In the sports context, evidence for muscle recovery in healthy individuals is less robust than often marketed.

TL;DR: Conditionally essential amino acid that is the primary fuel for gut lining cells. RCT evidence for IBS and leaky gut.

🦠Gut Health🛡️Immunity💪Muscle & Recovery
Last reviewed: 2026-03-12

Quick Facts

Evidence

Grade B

Studies

2

Interactions

2

Forms

1

Evidence Rating: Grade B — Moderate Evidence

Some RCTs with positive results, or strong observational evidence. More research may refine our understanding.

Interaction Warnings

AnticonvulsantsModerate

Glutamine converts to glutamate — theoretical seizure concern in epilepsy

LactuloseLow

May reduce glutamine gut benefit

Important Notes

  • Very safe at standard doses
  • Avoid in hepatic encephalopathy (glutamine → ammonia)
  • Primary fuel source for enterocytes

Clinical Evidence (2 studies)

L-glutamine for IBS-D

Zhou Q et al. (2019) — Gut Microbes

5g TID significantly reduced intestinal permeability in IBS-D; RCT

View on PubMed

Glutamine as conditionally essential amino acid

Garlick PJ (2001) — J Nutr

Review establishing glutamine as conditionally essential

View on PubMed

Alternatives to Consider

These supplements target similar goals and may be worth considering alongside or instead of Glutamine.

Ginger

Grade A

Excellent evidence for anti-nausea effects (pregnancy, chemotherapy, post-op). Also anti-inflammatory with COX-2 inhibition.

🦠 Gut Health🛡️ Immunity

NAC (N-Acetyl Cysteine)

Grade B

Precursor to glutathione (master antioxidant). Strong evidence for respiratory health, liver support, and psychiatric conditions.

🛡️ Immunity🦠 Gut Health

Probiotics

Grade B

Beneficial bacteria for gut health. Strain selection matters — L. rhamnosus GG, B. infantis 35624, and S. boulardii are best-studied.

🦠 Gut Health🛡️ Immunity

Related Supplements

Bromelain

Grade B — Moderate Evidence

Proteolytic enzyme from pineapple with evidence for reducing inflammation, swelling, and pain. Comparable to NSAIDs in some studies. Must take on empty stomach for systemic effects.

NAC (N-Acetyl Cysteine)

Grade B — Moderate Evidence

Precursor to glutathione (master antioxidant). Strong evidence for respiratory health, liver support, and psychiatric conditions.

Probiotics

Grade B — Moderate Evidence

Beneficial bacteria for gut health. Strain selection matters — L. rhamnosus GG, B. infantis 35624, and S. boulardii are best-studied.

Ginger

Grade A — Strong Evidence

Excellent evidence for anti-nausea effects (pregnancy, chemotherapy, post-op). Also anti-inflammatory with COX-2 inhibition.

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⚕️ Important Disclaimer

This information is for educational purposes only. It is not medical advice. Always consult a healthcare provider before starting any supplement regimen, especially if you take medications or have health conditions.

DoseGrade does not sell supplements and has no affiliate relationships with supplement manufacturers.