VitalMatrix
Amino AcidsModerate

L-Glutamine

Also known as Glutamine

L-Glutamine is the most abundant amino acid in the body and the primary fuel source for intestinal cells and immune cells. Under stress, surgery, illness, or intense exercise, demand outpaces supply. Supplementation has the strongest clinical evidence for restoring gut barrier integrity, reducing intestinal permeability ('leaky gut'), and supporting immune function during periods of high physiological stress.

Gut healthImmunityRecovery
By the Vital Matrix Editorial TeamReviewed by the Vital Matrix Research TeamLast updated June 25, 2026Moderate2 citations
Where to buy(affiliate links — we may earn a commission, which never changes our ratings)Nootropics DepotiHerb

Benefits

Supports gut barrier integrity

Moderate

Glutamine is the primary fuel for enterocytes (gut lining cells). Supplementation reduces intestinal permeability and supports recovery of the gut lining after illness, stress, or intense exercise.

Immune support during stress

Moderate

Lymphocytes and macrophages rely heavily on glutamine. Clinical trials in surgical and critically ill patients show improved immune markers with supplementation.

Reduces exercise-induced gut permeability

Moderate

Endurance athletes commonly experience increased gut permeability during prolonged exertion; glutamine attenuates this effect.

Pros & cons

Pros

  • Strong mechanistic rationale for gut health
  • Very safe at typical doses
  • Inexpensive in powder form

Cons

  • Evidence weaker for muscle preservation in healthy athletes than once believed
  • Powder has a slightly sweet flavour that some find unpleasant in high doses

Side effects

GI discomfort at high doses

Large doses can cause bloating or cramping in some people.

Mild

How to take it

Typical dose

5–15 g per day

Timing

With meals or post-workout for gut support; spread across the day

Common forms

Powder (most common)Capsules

Tip: 5 g/day is sufficient for general gut support. Clinical gut-permeability protocols often use 15–30 g/day split across meals.

What the research says

  1. [1]Glutamine and gut permeability

    Moderate

    Supplementation reduces markers of intestinal permeability in critically ill patients, surgical patients, and endurance athletes.

    Clinical and exercise trials · 2017PubMed

  2. [2]Glutamine and immune function

    Moderate

    Perioperative glutamine supplementation reduces infection rates and hospital stay duration in multiple clinical trials.

    Surgical trials · 2015PubMed

How L-Glutamine interacts

Synergies, absorption effects, and cautions between L-Glutamine and other supplements in the matrix.

L-Glutamine and its direct connections · click a node to open its guide

Synergy
Probiotics

Glutamine restores the gut lining while probiotics help balance the microbiome, a complementary gut-health stack.

Compare the pairing
Synergy
Glycine

Both are conditionally essential under stress and support gut and immune function through complementary pathways.

Compare the pairing
Synergy
Creatine

Common in post-workout recovery stacks; glutamine for gut integrity and creatine for muscle energy replenishment.

Compare the pairing
Synergy
Inulin

Glutamine helps restore the gut lining while inulin feeds beneficial bacteria, a complementary gut-health stack.

Compare the pairing
See it on the matrix

Frequently asked questions

What is L-Glutamine used for?

L-Glutamine is most commonly used for gut health, immunity, and recovery. Glutamine is the primary fuel for enterocytes (gut lining cells). Supplementation reduces intestinal permeability and supports recovery of the gut lining after illness, stress, or intense exercise.

How much L-Glutamine should I take?

A typical dose is 5–15 g per day. 5 g/day is sufficient for general gut support. Clinical gut-permeability protocols often use 15–30 g/day split across meals. Start at the lower end and confirm the right dose for you with a healthcare professional.

When is the best time to take L-Glutamine?

Recommended timing: With meals or post-workout for gut support; spread across the day.

What are the side effects of L-Glutamine?

Reported side effects include gi discomfort at high doses. Large doses can cause bloating or cramping in some people.

Who should be careful with L-Glutamine?

Caution in individuals with liver disease or seizure disorders, glutamine can influence ammonia and glutamate metabolism. Speak with a healthcare professional if any of these apply to you.

Important cautions

  • Caution in individuals with liver disease or seizure disorders, glutamine can influence ammonia and glutamate metabolism.
  • Not for use in patients with active cancer without oncologist approval.

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Compare L-Glutamine with

Weighing your options? See how L-Glutamine stacks up against similar supplements.

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