Glutamine
L-glutamine
Also known as: GLN · glutamate · glutaminate · levoglutamide · levoglutamine · L-glutamic acid 5amide · l-glutamine · Q
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Adjunctive treatment of GI inflammatory conditions | 0.5 grams/kg PO daily | PO | q24h | — | 🌎 NA |
| Adjunctive treatment of GI inflammatory conditions | 0.5 gram/kg/day PO divided twice a day | PO | q12h | — | 🌎 NA |
| Adjunctive treatment of GI inflammatory conditions (for animals not eating) | 0.5 grams/kg per day divided into 2-3 doses | PO | q8-12h | — | 🌎 NA |
- Adjunctive treatment of GI inflammatory conditions: Administer in water or food
- Adjunctive treatment of GI inflammatory conditions (for animals not eating): Dissolved in drinking water
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Adjunctive treatment of GI inflammatory conditions | 0.5 grams/kg PO daily | PO | q24h | — | 🌎 NA |
| Adjunctive treatment of GI inflammatory conditions | 0.5 gram/kg/day PO divided twice a day | PO | q12h | — | 🌎 NA |
| Adjunctive treatment of GI inflammatory conditions (for animals not eating) | 0.5 grams/kg per day divided into 2-3 doses | PO | q8-12h | — | 🌎 NA |
- Adjunctive treatment of GI inflammatory conditions: Administer in water or food
- Adjunctive treatment of GI inflammatory conditions (for animals not eating): Dissolved in drinking water
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Glutamine is a conditionally essential amino acid that plays a critical role in maintaining the health and integrity of the gastrointestinal (GI) tract, immune system, kidneys, and liver.
While healthy animals with adequate dietary protein intake synthesize sufficient glutamine in their skeletal muscles, patients under severe metabolic stress (such as those with critical illness, severe trauma, or undergoing chemotherapy) may consume more glutamine than they can produce. This depletion can lead to progressive muscle wasting and compromise the intestinal mucosal barrier, resulting in atrophy, ulceration, or necrosis of the intestinal epithelium.
Clinical Highlights:
- Primarily used as a GI protectant and to promote mucosal healing in conditions like parvoviral enteritis, chemotherapy-induced enteritis, and pancreatitis.
- Clinical Pearl: Glutamine is the preferred respiratory fuel for enterocytes (intestinal absorptive cells) and colonocytes. Supplementation aims to directly nourish these cells and maintain the gut barrier function, preventing bacterial translocation.
- Generally very safe with a wide margin of safety, though clinical efficacy data in veterinary medicine remains mixed (e.g., some studies show no significant benefit in methotrexate-induced enteritis in cats).
Mechanism of action
Glutamine serves multiple vital physiological functions:
- Enterocyte Fuel: It is the primary metabolic fuel for rapidly dividing cells, particularly intestinal enterocytes and immune cells (lymphocytes, macrophages). Glutamine is metabolized via glutaminase to glutamate, which is then converted to alpha-ketoglutarate to enter the TCA (Krebs) cycle for ATP production.
- Precursor Molecule: It acts as a crucial nitrogen donor and precursor for the synthesis of glutathione (a major intracellular antioxidant), purines, pyrimidines, and other amino acids.
- Mucosal Integrity: By providing direct energy to the gut lining, it stimulates intestinal cell proliferation and differentiation, helping to maintain tight junctions and prevent increased intestinal permeability ("leaky gut") during times of severe stress or mucosal injury.
Safety & warnings
Contraindications
- Severe hepatic insufficiency
- Severe behavior disorders
- Epilepsy or seizure disorders
Adverse effects
- Generally well tolerated
- Potential CNS effects at very high dosages
- Increased serum ammonia or glutamate levels
Precautions
Use with caution in patients with severe hepatic insufficiency, severe behavior disorders, or epilepsy, as glutamine is partially metabolized into ammonia and glutamate. There is insufficient data documenting the safe use of glutamine during pregnancy or nursing.
Drug interactions
Glutamine could potentially decrease the efficacy of antiseizure medications because it is partially converted into glutamate, which acts as an excitatory neurotransmitter in the CNS.
Theoretically, glutamine may antagonize the ammonia-lowering effects of lactulose in patients being treated for hepatic encephalopathy.
Monitoring
- Clinical efficacy (improvement in GI signs, weight maintenance)
- Serum ammonia levels (in patients with compromised liver function)
- Serum glutamate levels
Pharmacokinetics
Distribution
Produced primarily in skeletal muscle and released into circulation.
Metabolism
Partially metabolized into ammonia and glutamate.
Overdose
Overdosages are unlikely to be harmful in healthy animals. In humans, intravenous doses of up to 40 grams per day have been tolerated without ill effects. However, because glutamine is partially metabolized to ammonia, patients with pre-existing hepatic insufficiency (liver disease) may be adversely affected and could develop signs of hepatic encephalopathy.
Available products
Formulations
- Tablets
- Powder
- Oral suspension (when dissolved in water)
Human-labeled
- L-glutamine 500 mg tablets
- Glutamine powder
- Glutamic acid 500 mg tablets
- Glutamic acid powder
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Glutamine tablets and powder should be stored in tight containers at room temperature.
Client information
What is Glutamine? Glutamine is a naturally occurring amino acid that helps provide energy to the cells lining the stomach and intestines. It is often used as a nutritional supplement to help the gut heal during severe illness, such as parvovirus, pancreatitis, or during chemotherapy.
- Administration: Glutamine can be administered with food. If your pet is not eating, the powder can be dissolved in their drinking water as directed by your veterinarian.
- Safety: It is generally very safe and well-tolerated.
- Precautions: Inform your veterinarian if your pet has a history of liver disease, seizures, or behavioral disorders, as glutamine may not be appropriate for them.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.