Glutamine

Pronunciation: GLOO-tah-meen.

Generic name
L-glutamine
Drug class
Amino acid; dietary/food supplement in its general-purpose form (not an approved drug); ALSO the active ingredient of an FDA-approved prescription product (Endari) for sickle cell disease in the United States
Form
Capsule, tablet, or powder (general supplement forms); single-dose oral powder packet, 5 g (Endari prescription product)
Route
Oral
Legal status
Dietary/food supplement (US, UK, EU, New Zealand) or listed/licensed complementary product (Canada, Australia) in its general-purpose form in every market reviewed. Separately, a specific prescription oral powder product (Endari) is FDA-approved in the United States only for sickle cell disease; the equivalent EU product (Xyndari) was formally rejected by the CHMP and its marketing authorisation application withdrawn in 2019, and no UK, Canada, Australia, or New Zealand approval of the prescription product was found.

Availability and supply rules vary by country

Trade names by country: United States

Australia: · Full directory

What L-glutamine is and how it works

Glutamine is an amino acid the body uses for many functions, including as fuel for cells lining the gut and the immune system. In its general form it is sold as a dietary/food supplement or listed complementary product -- not as an approved prescription or over-the-counter drug -- and commonly marketed for digestive support, immune support, or muscle recovery after exercise. Separately, a specific pharmaceutical-grade oral powder form of L-glutamine (brand name Endari) is FDA-approved in the United States to reduce the acute, painful complications of sickle cell disease. (4) (1)

Because general supplement glutamine is regulated as a food product rather than a medicine in every market reviewed, it has not gone through the same pre-market evidence and safety review as an approved drug, and marketed claims are not independently verified by a regulator. If you or a family member has sickle cell disease and has been prescribed Endari specifically, that is a distinct, clinician-directed prescription treatment with its own body-weight-based dosing schedule -- it is not the same as choosing a general glutamine supplement off a shelf, and the two should not be treated as interchangeable.

Mechanism of action: how L-glutamine works

Glutamine is a conditionally essential amino acid and a key fuel source for rapidly dividing cells, including enterocytes (gut lining cells) and immune cells. In sickle cell disease, oral L-glutamine is thought to improve the NAD redox potential in red blood cells, which may reduce the oxidative stress and cell adhesion changes that contribute to painful vaso-occlusive crises -- though the EU's CHMP concluded the submitted efficacy data did not adequately demonstrate a reduction in sickle cell crises or hospital visits. (1) (3)

What L-glutamine is used for

General dietary supplement for digestive, immune, or exercise-recovery support (self-selected, not independently verified)

Commonly marketed as a supplement intended to help restore plasma glutamine levels depleted after intense physical stress or exhaustive exercise, and to support digestive and immune system health during recovery. These are supplement marketing claims, not independently regulator-verified therapeutic indications. (6)

Reducing acute complications of sickle cell disease (FDA-approved prescription product, Endari, United States only)

Endari (L-glutamine oral powder) is FDA-approved to reduce the acute complications of sickle cell disease -- such as painful crises -- in adult and pediatric patients 5 years of age and older. This is a distinct, clinician-prescribed use of a specific pharmaceutical-grade product, not a general supplement indication, and this exact use is not currently authorised in the European Union (the equivalent product, Xyndari, was formally rejected) or confirmed authorised in the UK, Canada, Australia, or New Zealand. (1) (2)

Before taking L-glutamine

Do not take / not appropriate for

  • The Endari prescription product has no contraindications listed on its current FDA label, but should only be started, stopped, or dosed under your prescriber's direction -- never self-selected as a substitute for a general supplement, or vice versa. (United States) (1)
  • Avoid a general glutamine supplement if you have a known allergy or sensitivity to it, and discuss use with a clinician or pharmacist first if you have significant liver disease, a seizure disorder, or sensitivity to monosodium glutamate (MSG), since glutamine is metabolised toward related compounds in the body. (all countries) (4)

Tell your clinician about

  • Whether you have sickle cell disease and have been specifically prescribed Endari, versus considering a general over-the-counter glutamine supplement -- these are different products with different evidence bases and dosing.
  • Any diagnosed liver disease, seizure disorder, kidney condition, or known sensitivity to MSG.
  • All other medicines and supplements you take.
  • Whether you are pregnant, planning pregnancy, or breastfeeding -- pregnancy safety data for both the general supplement and the Endari prescription product are limited.
  • Your age, since the Endari prescription product's safety and effectiveness have not been established in children under 5, and clinical trials did not include enough patients 65 and older to know whether they respond differently.
(1) (4)

How to take L-glutamine

  • General supplement products: follow the manufacturer's label directions -- there is no regulator-established therapeutic dose for glutamine as a supplement in any market reviewed.
  • Endari prescription product (United States only): dosed strictly by body weight and taken exactly as prescribed, mixed with a cold or room-temperature beverage (about 8 oz) or soft food (4-6 oz), twice daily -- never self-directed.
  • Do not treat a general glutamine supplement and the Endari prescription product as interchangeable, even though both contain the same amino acid.
(1) (6)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6) (7) (8)

Missed dose

For general supplement use, simply resume your usual routine at the next planned use -- there is no medical need to double up. For the Endari prescription product, follow your prescriber's specific instructions for a missed dose rather than guessing.

Overdose

If you or someone else has taken a very large amount of a glutamine product, or develops symptoms such as severe stomach upset, unusual confusion, or seizure-type symptoms, contact a pharmacist, doctor, or poison control service for advice. (1)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

For the Endari prescription product, the most common side effects reported in more than 10% of patients were constipation, nausea, headache, abdominal pain, cough, pain in the arms or legs, back pain, and chest pain.

What to notice: For the Endari prescription product, the most common side effects reported in more than 10% of patients were constipation, nausea, headache, abdominal pain, cough, pain in the arms or legs, back pain, and chest pain.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

General supplement use is generally well tolerated at typical doses; mild gastrointestinal upset has been reported by some users of amino acid supplements generally.

What to notice: General supplement use is generally well tolerated at typical doses; mild gastrointestinal upset has been reported by some users of amino acid supplements generally.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (6)

Serious warnings

Signs of a serious allergic reaction — emergency

Symptoms: Swelling of the face, lips, tongue, or throat; difficulty breathing; widespread rash or hives.

Action: Stop using it and seek emergency medical help immediately. (4)

Confusing a general glutamine supplement with the Endari prescription product, or vice versa — high caution

Symptoms: Not applicable -- this is a product-selection safety point rather than a symptom to watch for.

Action: Check carefully which type of product you have. The Endari prescription product is dosed by body weight for a specific medical condition (sickle cell disease) under a prescriber's direction; a general supplement is not a substitute for it if you have been prescribed it, and Endari's specific dosing schedule should not be applied to a general supplement. (1)

Interactions

  • No specific drug-drug interactions are listed on the current Endari prescribing information; nonetheless, tell your clinician about all other medicines and supplements you take before starting any glutamine product. (1)
  • People with a known sensitivity to monosodium glutamate (MSG) should use glutamine supplements with caution, since the body converts glutamine into related compounds. (4)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

No animal reproduction studies have been conducted for the Endari prescription product, and pregnancy safety data are not available; general supplement safety data in pregnancy are also limited. Discuss use with a clinician before taking any glutamine product during pregnancy. (1) (2) (3) (4) (5) (6) (7) (8)

Breastfeeding

Specific safety data during breastfeeding is limited for both the general supplement and the Endari prescription product; discuss with a clinician before use. (1) (2) (3) (4) (5) (6) (7) (8)

Children

Endari's safety and effectiveness have not been established in children younger than 5 years old. General supplement use in children is not well established in the sources reviewed and should be discussed with a clinician. (1) (2) (3) (4) (5) (6) (7) (8)

Elderly

Endari clinical trials did not include sufficient numbers of patients 65 and older to determine whether they respond differently than younger patients; dose selection for an older adult starting Endari should be cautious. No specific restriction was identified for general supplement use. (1) (2) (3) (4) (5) (6) (7) (8)

Hepatic_impairment

Advanced liver disease (such as cirrhosis) is a recognised reason for caution with glutamine supplementation generally, since glutamine is broken down toward ammonia in the body; discuss with a clinician if you have significant liver disease. (1) (2) (3) (4) (5) (6) (7) (8)

Renal_impairment

No specific guidance identified in the sources reviewed for general supplement use; Endari's label does not specify renal dose adjustment. (1) (2) (3) (4) (5) (6) (7) (8)

Monitoring

Before starting

  • Confirm whether you need a general supplement or have been prescribed the Endari prescription product for sickle cell disease
  • Check other medicines/supplements and relevant medical history (liver disease, seizure disorder, MSG sensitivity)

During treatment

  • For the Endari prescription product, monitoring is directed by the treating clinician as part of managing sickle cell disease.
  • For general supplement use, there is no regulator-mandated monitoring; if you notice any concerning symptoms, stop using it and consult a pharmacist or doctor promptly.
(1)

Storage

General supplement products: store per the label, typically at room temperature, away from moisture, out of reach of children. Endari packets: store at room temperature and use as directed by the pharmacy label.

Professional information

Clinician-facing context only. General-purpose glutamine is not an approved drug, so there is no regulator-approved prescribing information for the supplement form; this section reflects the supplement/natural-health-product source material for general use, and the genuine FDA prescribing information for the separate Endari product.

United States / United Kingdom / European Union / Canada / Australia / New Zealand

Indication: General supplement use (self-selected, label-directed)

Dose summary: No regulator-established therapeutic dose; follow the specific product's label directions.

Renal context: Not applicable -- not a regulated drug with renal dosing guidance in the sources reviewed. (6)

United States only

Indication: Sickle cell disease, acute complications (Endari)

Dose summary: Body-weight-based: <30 kg = 5 g/dose (10 g/day); 30-65 kg = 10 g/dose (20 g/day); >65 kg = 15 g/dose (30 g/day), twice daily.

Renal context: Not specified on the current label. (1)

Mechanism of action

Hepatic guidance

Caution advised in significant liver disease for general supplement use, given glutamine's metabolism toward ammonia-related pathways; no specific hepatic dose adjustment is specified on the Endari label.

Overdose note

No specific antidote; manage suspected overdose with supportive care and advice from a poison control service or clinician. (1) (3)

Frequently asked questions

Is glutamine a prescription medicine?

It depends which product you mean. General-purpose glutamine, in every market reviewed (United States, United Kingdom, European Union, Canada, Australia, New Zealand), is regulated as a dietary/food supplement or a low-risk complementary/natural-health product, not an approved prescription or over-the-counter drug. Separately, a specific pharmaceutical-grade product (Endari) is FDA-approved in the United States only to reduce acute complications of sickle cell disease -- the equivalent EU product (Xyndari) was formally rejected and its application withdrawn in 2019, and no UK, Canada, Australia, or New Zealand approval of this prescription product was found. (4) (1) (3)

What is glutamine used for?

As a general supplement, it is commonly marketed to help restore glutamine levels after intense physical stress and to support digestive and immune health during recovery -- these are supplement marketing claims, not independently regulator-verified therapeutic indications. Separately, the FDA-approved prescription product Endari is used specifically to reduce acute, painful complications of sickle cell disease in the United States. (6) (1)

Why isn't the sickle cell disease glutamine product (Endari) available in Europe?

The manufacturer applied for EU approval under the brand name Xyndari, but the European Medicines Agency's Committee for Medicinal Products for Human Use (CHMP) maintained a negative opinion, concluding that the submitted data did not demonstrate Xyndari was effective at reducing the number of sickle cell disease crises or hospital visits. The manufacturer withdrew the application in September 2019 as a result, so this specific prescription product is not currently authorised in the EU. (3)

What is the mechanism of action of L-glutamine?

Glutamine is a conditionally essential amino acid and a key fuel source for rapidly dividing cells, including enterocytes (gut lining cells) and immune cells. In sickle cell disease, oral L-glutamine is thought to improve the NAD redox potential in red blood cells, which may reduce the oxidative stress and cell adhesion changes that contribute to painful vaso-occlusive crises -- though the EU's CHMP concluded the submitted efficacy data did not adequately demonstrate a reduction in sickle cell crises or hospital visits. (1) (3)

What is the generic name of Glutamine?

The generic name is L-glutamine. (4) (1)

What class of drug is L-glutamine?

Glutamine is classed as: Amino acid; dietary/food supplement in its general-purpose form (not an approved drug); ALSO the active ingredient of an FDA-approved prescription product (Endari) for sickle cell disease in the United States. (4) (1)

References

  1. ENDARI (L-glutamine oral powder) -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information, Emmaus Medical, Inc. · United States · accessed 2026-07-30 · source 1
  2. FDA approves new treatment for sickle cell diseaseU.S. Food and Drug Administration -- press announcement · United States · accessed 2026-07-30 · source 2
  3. Emmaus Life Sciences Announces Withdrawal of Marketing Authorization Application to European Medicines Agency (Xyndari, oral L-glutamine)Emmaus Life Sciences (manufacturer) press release, corroborating EMA/CHMP referral outcome · European Union · accessed 2026-07-30 · source 3
  4. Dietary Supplements -- regulatory framework and New Dietary Ingredient backgroundU.S. Food and Drug Administration -- Dietary Supplements regulatory framework (DSHEA 1994) · United States · accessed 2026-07-30 · source 4
  5. MHRA guidance on determining borderline products and medicinal status (food supplements, amino acids)UK Medicines and Healthcare products Regulatory Agency (MHRA) -- borderline products guidance · United Kingdom · accessed 2026-07-30 · source 5
  6. L-Glutamine -- Licensed Natural Health Product, NPN 80130534 (and related NPNs)Health Canada, Licensed Natural Health Products Database (LNHPD) · Canada · accessed 2026-07-30 · source 6
  7. L-Glutamine -- ARTG entries (e.g. 478767, 410279, 351662)Therapeutic Goods Administration (TGA), Australia · Australia · accessed 2026-07-30 · source 7
  8. Regulation of Dietary Supplements (Dietary Supplements Regulations 1985)Medsafe (New Zealand regulator) -- Dietary Supplements Regulations 1985 framework · New Zealand · accessed 2026-07-30 · source 8

Brand names by country

Single-ingredient L-glutamine names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • Endari (1) (2)FDA approved 2017 currently labeled · 5 g oral powder packet · Emmaus Medical, Inc.
View brands in additional countries.

This page provides general reference information about glutamine, both as a dietary supplement and as the active ingredient of the FDA-approved prescription product Endari, and is not a substitute for advice from a pharmacist, dietitian, or doctor. General glutamine supplements are not independently evaluated by regulators for the claims made about them. If you have been prescribed Endari for sickle cell disease, follow your clinician's instructions rather than general supplement guidance.

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