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Glutamine

Glutamine

Best for

Calm ulcerative colitis flares

Likely strong benefit · 1 meta-analysis , n=198

42 papers · 7 claims · 116 outcomes scored · 5 positive

Evidence overview

Evidence overview Likely strong benefit

Glutamine shows likely strong benefit for calming ulcerative colitis flares in people with ulcerative colitis and supporting intestinal barrier function.

  • Across 1 study (n=198), glutamine improved ulcerative colitis flare severity, above the noticeable-change threshold.2
  • Glutamine evidence spans 42 papers and 116 outcomes, with one strong claim and several early signals.
  • Benefits concentrate in gut-related uses; exercise recovery trials do not show the same strength.

Outcomes

What glutamine actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect Evidence Dose Weeks Rank
Calm ulcerative colitis flares Likely strong benefit
large 		1 meta-analysis n=198 Meta-analyzed — — #2/5
Reduce diarrhea and recover faster Large effect, needs confirmation
large 		3 RCTs n=106 15–20 g 2–8 wk #7/17
Extend remission in Crohn's disease Not enough research
moderate 		1 meta-analysis n=18 Meta-analyzed — — #2/3
Recover faster after exercise Faint early signal
small 		5 RCTs n=82 0.1–6000 g 1–6 wk #9/35
Tighten the intestinal barrier Likely real but unnoticeable
trivial 		9 meta-analyses n=828 Meta-analyzed 0.2–8910 g 1–8 wk #1/7
Improve overall digestive comfort Not enough research
1 RCT n=— 250 mg/kg — —
Reduce inflammatory bowel flare-ups Not enough research
1 RCT n=— 3 g 1 wk —

Forms & standardisation

The evidence base centers on plain oral L-glutamine powder or capsules, not a special branded blend. If you are shopping, the label that matters most is the one that lists glutamine as the active ingredient, because that is what the trials actually tested.123

Risk profile

Adverse events and known drug interactions

Safety events

grade 3 or worse oral mucositis severe
mucositis (oral cavity, pharynx, larynx) severe
oral mucositis (treatment-related severe cases caused chemo delay) severe
oral mucositis (Grade III) severe
dysphagia (Grade III) severe
Any grade 2 AE possibly related to study drug moderate
nausea mild
headache mild

Drug interactions

Gentamicin moderate increases concentration

Co-studied with

Supplements that share evidence with glutamine

  • Glucose 1 shared outcome · d=1.30

Frequently asked

Common questions

What does glutamine do for your gut?

It gives intestinal cells a ready fuel source and supports the barrier that keeps gut contents from irritating the rest of your body.12

How much glutamine do people use in studies?

The gut-focused trials cluster around 4 to 30.5 g/day for barrier support and 15 to 18 g/day for diarrhea, with a small inflammation study using 3 g/day.123

How long does glutamine take to work?

The gut-barrier studies ran about 1.5 to 8 weeks, and the diarrhea studies ran about 2 to 8 weeks, so think in weeks, not days.13

Is glutamine good for exercise recovery?

The exercise studies are small and the signal is faint, so glutamine does not stand out as a reliable recovery supplement.4

Sources

  1. 1. Glutamine and intestinal barrier function in human trials
  2. 2. Glutamine supplementation in ulcerative colitis trials
  3. 3. Oral glutamine for diarrhea trials
  4. 4. Glutamine supplementation after exercise trials

Generated May 15, 2026

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