Glutamine

Q: 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**.

Q: 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.

Best for

Calm ulcerative colitis flares

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

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

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 size Evidence Dose Weeks Rank

Calm ulcerative colitis flares Likely strong benefit

Longer calm stretches between flares as damaged gut tissue actually heals.

1 meta-analysis n=198 — — #2/5

28427169

large

1 meta-analysis n=198 Meta-analyzed I²=78%

—

#2 /5

Reduce diarrhea and recover faster Large effect, needs confirmation

Fewer loose stools, shorter episodes, and less fluid loss.

3 RCTs n=106 15–20 g 2–8 wk #7/17

11115819·30108163·34977110

large

3 RCTs n=106

15–20 g

2–8 wk

#7 /17

Extend remission in Crohn's disease Not enough research

Lower gut inflammation gives the intestinal wall time to heal between flares.

1 meta-analysis n=18 — — #2/3

26853855

moderate

1 meta-analysis n=18 Meta-analyzed

—

#2 /3

Recover faster after exercise Faint early signal

Less soreness, less inflammation, and quicker return to form after hard training.

5 RCTs n=82 0.1–6000 g 1–6 wk #9/35

29511657·34204359·38193521·24868432 +1 more

small

5 RCTs n=82

0.1–6000 g

1–6 wk

#9 /35

Tighten the intestinal barrier Likely real but unnoticeable

Seals the gaps that let bacterial fragments leak into your bloodstream.

9 meta-analyses n=828 0.2–8910 g 1–8 wk #1/7

11115819·24714829·26266659·26853855 +5 more

trivial

9 meta-analyses n=828 Meta-analyzed I²=97%

0.2–8910 g

1–8 wk

#1 /7

Improve overall digestive comfort Not enough research

Less cramping, rumbling, and unease throughout your gut.

1 RCT n=— 250 mg/kg —

29058112

—

1 RCT n=—

250 mg/kg

—

Reduce inflammatory bowel flare-ups Not enough research

Your immune system dials back its attack on the gut lining.

1 RCT n=— 3 g 1 wk

32826717

—

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

Track glutamine in the app

Log doses, check interactions, compare it to alternatives — all backed by the same evidence base.

One email when we launch. No spam, no selling.

Sources

Generated May 15, 2026