Glutamine
Useful mainly for patients recovering from critical illness, major burns, or surgery; chemotherapy patients with oral mucositis.
Quick decision guide
May help most
Patients recovering from critical illness, major burns, or surgery; chemotherapy patients with oral mucositis
Common dosing range
5–10 g/day for general use; 20–30 g/day in clinical settings under supervision
When to expect effects
Days to weeks
Watch out for
Avoid in liver failure, kidney failure, seizure disorders, and hepatic encephalopathy — glutamine metabolism produces ammonia that impaired organs cannot clear
What is it
Glutamine is a conditionally essential amino acid that is the most abundant free amino acid in human blood and skeletal muscle. The body normally makes enough on its own, but demand can outstrip supply during severe illness, major surgery, prolonged endurance exercise, or trauma.
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
critical illness and burn recovery Limited Evidence | Reduced infection rates and shorter ICU/hospital stays in several trials; effect size varies by route and population | ICU patients, major burn patients, post-surgical patients with catabolic stress | Days |
chemotherapy-related mucositis Limited Evidence | Modest reduction in mucositis severity and duration in some trials | Patients undergoing chemotherapy or head/neck radiation with oral or GI mucositis | Days to weeks |
gut barrier support after illness or stress Mixed Evidence | Modest improvement in intestinal permeability markers in some trials | Post-surgical or post-critical-illness patients with gut barrier compromise | Days to weeks |
critical illness and burn recovery
- Effect
- Reduced infection rates and shorter ICU/hospital stays in several trials; effect size varies by route and population
- Best fit
- ICU patients, major burn patients, post-surgical patients with catabolic stress
- Time
- Days
chemotherapy-related mucositis
- Effect
- Modest reduction in mucositis severity and duration in some trials
- Best fit
- Patients undergoing chemotherapy or head/neck radiation with oral or GI mucositis
- Time
- Days to weeks
gut barrier support after illness or stress
- Effect
- Modest improvement in intestinal permeability markers in some trials
- Best fit
- Post-surgical or post-critical-illness patients with gut barrier compromise
- Time
- Days to weeks
Evidence for 3 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
critical illness and burn recovery
Disease adjunctPlasma glutamine drops substantially during critical illness while demand from gut epithelium and immune cells spikes. Multiple RCTs and meta-analyses of parenteral and enteral glutamine in ICU patients show reductions in infection rates and length of stay, though large trials (REDOXS, METAPLUS) using very high doses paradoxically showed harm in the sickest patients. The benefit/harm window depends on dose, route, and patient severity.
Bottom line: Glutamine supplementation supports recovery in hospitalized critically ill patients at moderate doses — but only under medical supervision, as very high doses have been harmful in some ICU populations.
Evidence is mixed
The REDOXS trial found increased mortality with high-dose (0.5 g/kg/day) glutamine in critically ill patients with multi-organ failure, cautioning against high-dose use in the sickest patients.
chemotherapy-related mucositis
Disease adjunctSeveral RCTs show that oral glutamine supplementation reduces the severity and duration of oral mucositis in patients undergoing chemotherapy, particularly with fluorouracil-based regimens. The effect is modest and not universal across all chemotherapy types. Use must be coordinated with oncology teams as glutamine could theoretically protect tumors in some contexts.
Bottom line: Oral glutamine may modestly reduce chemotherapy-related mucositis — discuss with your oncologist before use, as appropriateness varies by cancer type and regimen.
gut barrier support after illness or stress
Mechanism onlyGlutamine is the primary fuel for intestinal enterocytes and is required for maintaining tight junction integrity. Animal and in vitro models demonstrate that glutamine deprivation increases gut permeability. Human trial data on intestinal permeability markers (lactulose/mannitol ratio) are mixed and mostly conducted in surgical or ICU settings. No robust evidence exists that glutamine supplementation improves gut function in healthy people.
Bottom line: The gut-protective mechanism is biologically sound, but clinical evidence is limited to ill or post-surgical populations — not healthy individuals.
How it works
How to take it
What to track
2 commercial forms
Compare the main delivery options and what they’re best suited for.
L-glutamine (free form)
The most common and least expensive form, available as a tasteless powder or capsule. Mix into water and drink promptly because glutamine slowly hydrolyzes to ammonia and glutamate in solution.
Standard supplemental form. Stable in dry powder; degrades in solution over hours.
Glutamine peptides (e.g., alanyl-glutamine)
Used in parenteral nutrition and some sports drinks because the dipeptide form survives aqueous storage longer than free glutamine. For oral home use the cost premium rarely justifies the modest advantage.
More stable in solution and slightly better absorbed in clinical settings.
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Serious risks
Hyperammonemia in people with liver or kidney disease
Potential harm at very high doses (>0.5 g/kg/day) in critically ill patients with multi-organ failure
Who should avoid it
- Cirrhosis or advanced liver disease
- Kidney failure
- Seizure disorder or history of hepatic encephalopathy
- Bipolar disorder (glutamine converts to glutamate, an excitatory neurotransmitter)
- People on low-protein medical diets for hepatic encephalopathy
Pregnancy & breastfeeding
Safety data are limited; do not exceed dietary amino acid intake during pregnancy without clinician guidance.
Interactions
Glutamine is converted to glutamate (excitatory neurotransmitter), potentially reducing seizure threshold
Glutamine metabolism generates ammonia, counteracting lactulose used to reduce ammonia in liver disease
Protocols featuring Glutamine
Evidence-backed routines where Glutamine plays a role.
Daily Gut Foundation
digestion
The gut-supplement market is overrun with "leaky gut" cure-alls and proprietary blends. The actual evidence is narrower than the marketing suggests. What is well-supported: a diverse fiber intake feeds beneficial bacteria, specific probiotic strains reduce antibiotic-associated diarrhea and shorten gastroenteritis episodes, and L-glutamine has some evidence for intestinal barrier support. This protocol is the conservative foundation — start here before chasing specific gut conditions with more aggressive interventions.
IBD Support (Crohn's & Ulcerative Colitis)
autoimmune
Inflammatory bowel disease (IBD) affects roughly 3 million Americans across two main forms: Crohn''s disease (can involve any segment of the GI tract, transmural inflammation, often complicated by strictures, fistulas, and surgical resections) and ulcerative colitis (continuous mucosal inflammation limited to the colon, with bloody diarrhea and urgency as hallmark symptoms). This is fundamentally different from IBS (irritable bowel syndrome), which is a functional disorder without structural damage. IBD involves chronic, often progressive intestinal inflammation, ulceration, and sometimes systemic complications (uveitis, arthritis, primary sclerosing cholangitis, increased colorectal cancer risk). The modern treatment revolution is biologic and small-molecule therapy: 5-ASAs (mesalamine for UC), corticosteroids (short-term flare control only), immunomodulators (azathioprine, methotrexate), TNF inhibitors (infliximab/Remicade, adalimumab/Humira), integrin antagonists (vedolizumab/Entyvio), IL-12/23 inhibitors (ustekinumab/Stelara, risankizumab/Skyrizi), and JAK inhibitors (tofacitinib, upadacitinib). These are genuinely transformative — biologic-era outcomes have dramatically reduced surgery rates, steroid dependence, and hospitalizations. This protocol is an ADJUNCTIVE supplement layer for adults with an established IBD diagnosis under gastroenterology care — NOT a substitute for proper medical therapy. It targets: nutrient deficiencies common in IBD due to malabsorption and inflammation (vitamin D, iron, B12), gut barrier support (L-glutamine), and inflammation modulation (omega-3 EPA, curcumin). Trial evidence is strongest for curcumin (Lang 2015 — curcumin + mesalamine outperformed mesalamine alone in UC remission) and vitamin D normalization (Ananthakrishnan 2013 — associated with reduced surgery risk in Crohn''s). CRITICAL: Beware "IBD cure" marketing. There is a substantial ecosystem promising that diet alone, supplements alone, or "leaky gut protocols" can reverse IBD. The honest evidence: supplements + diet measurably help but do NOT replace biologics or immunomodulators in moderate-to-severe disease. Stopping a biologic based on supplement marketing is one of the most reliable ways to lose intestinal tissue.
SIBO / IBS Support
digestion
Small intestinal bacterial overgrowth (SIBO) and irritable bowel syndrome (IBS) overlap significantly — up to 60% of IBS patients test positive for SIBO via lactulose or glucose breath testing. The conventional treatment is rifaximin (a non-absorbed antibiotic) ± neomycin for methane-dominant cases. Herbal antimicrobials have surprisingly competitive trial evidence — a 2014 trial found herbal protocols comparable to rifaximin for SIBO eradication. This stack pairs antimicrobial botanicals (berberine, oregano oil) with gut-barrier and motility support (L-glutamine, peppermint oil, prokinetic herbs). If you suspect SIBO, get a breath test first — empirically treating without testing leads to wasted protocols and prolonged symptoms. If your IBS is moderate-to-severe, see a gastroenterologist; treatment-resistant cases benefit from proper workup (celiac panel, calprotectin, sometimes endoscopy).
Food sources
| Food | Amount | %DV |
|---|---|---|
| Beef | ~1.2 g per 3 oz | — |
| Eggs | ~0.6 g per large egg | — |
| Tofu | ~0.6 g per half cup | — |
| Cottage cheese | ~1.7 g per cup | — |
| Cabbage | ~0.3 g per cup | — |
| Spinach | ~0.3 g per cup raw | — |
| Lentils | ~0.6 g per cup cooked | — |
Beef
- Amount
- ~1.2 g per 3 oz
- %DV
- —
Eggs
- Amount
- ~0.6 g per large egg
- %DV
- —
Tofu
- Amount
- ~0.6 g per half cup
- %DV
- —
Cottage cheese
- Amount
- ~1.7 g per cup
- %DV
- —
Cabbage
- Amount
- ~0.3 g per cup
- %DV
- —
Spinach
- Amount
- ~0.3 g per cup raw
- %DV
- —
Lentils
- Amount
- ~0.6 g per cup cooked
- %DV
- —
Choosing a product
What to look for on the label — and what to be skeptical of.
Look for…
Be skeptical of…
Frequently asked questions
Do I need glutamine if I eat plenty of protein?⌄
Probably not. A diet with 0.8 to 1.6 grams of protein per kilogram of body weight typically supplies 3 to 6 grams of glutamine per day from food, plus your body makes 50 to 80 grams on its own. Supplementation is most useful in catabolic states (illness, surgery, severe training) where demand temporarily exceeds supply.
Does glutamine help build muscle?⌄
On its own, no. Trials testing glutamine for muscle hypertrophy or strength have been largely negative in healthy lifters with adequate protein. Leucine and total protein intake are far more important for muscle growth.
Will glutamine fix leaky gut?⌄
Glutamine genuinely fuels intestinal cells and supports tight junctions, and it shows benefit in measurable intestinal permeability after burns or surgery. 'Leaky gut syndrome' as marketed to healthy adults is not a recognized diagnosis, and evidence for symptom relief in IBS or other functional gut disorders is mixed.
Can I take glutamine on an empty stomach?⌄
Yes, and that is the most common protocol. Empty-stomach dosing slightly speeds absorption, which is why many users take 5 grams first thing in the morning or post-workout.
Is glutamine safe long-term?⌄
Short and medium-term studies up to several months at 5 to 30 grams per day have shown few side effects in healthy adults. Long-term safety beyond a year has not been formally studied. People with liver or kidney disease should not take it without supervision.
References by claim
critical illness and burn recovery
Heyland et al., 2022 — PubMed (2022) link
chemotherapy-related mucositis
Track Glutamine with Pilora
Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.
Coming to App StoreDisclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.