L-glutamine
L-glutamine is an amino acid medicine used to reduce the acute complications of sickle cell disease in adults and children 5 years and older.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 3 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
L-glutamine (Endari) is an amino acid powder that reduces the acute complications of sickle cell disease in people 5 and older, likely by raising glutathione, a natural antioxidant that protects fragile sickle red blood cells from oxidative stress (chemical wear and tear); it is often added to hydroxyurea, and L-glutamine products have been on the U.S. market since the 1980s, with generics available. Most people tolerate it well, and the side effects they notice are usually constipation, nausea, headache or stomach pain. There is no boxed warning, but get medical help right away for chest pain, since it can also signal a serious sickle cell complication.
Clinical pearls
- Mix each dose right before taking it in a cold or room-temperature drink or soft food like applesauce; avoid hot liquids.
- It is a preventive medicine taken twice daily, and it will not stop a pain crisis that has already started.
- Store-bought glutamine supplements are not interchangeable with the prescription powder, so do not swap one for the other.
- No interaction studies exist, so give every prescriber and pharmacist a full list, including supplements, and mention pregnancy or breastfeeding plans.
Patient information guide A plain-language walkthrough of L-glutamine, written from its FDA label.
What L-glutamine is used for
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L-glutamine is an amino acid used for one condition.
- L-glutamine oral powder reduces the acute complications of sickle cell disease in adults and children 5 years and older.
How L-glutamine works
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The exact way L-glutamine works in sickle cell disease isn't fully understood. Sickle red blood cells are more prone to oxidative damage, which may contribute to red cell breakdown (hemolysis) and blocked blood vessels (vaso-occlusive events).
L-glutamine may help by increasing reduced glutathione, which improves the NAD redox potential (the cell's protective chemical balance) in sickle red blood cells.
L-glutamine dosage
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L-glutamine oral powder is taken by mouth twice a day, with the amount based on body weight. Mix it right before taking with a cold or room-temperature drink or a little soft food. It doesn't have to dissolve completely.
- It can be taken with or without food.
- Follow your prescriber's directions and the label.
Dosing details from the FDA-approved label
From the L-glutamine prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Patients weighing less than 30 kg (less than 66 pounds)
- 5 grams per dose orally, twice per day (10 grams per day)
- 1 packet per dose, 2 packets per day
- Mix each dose in 8 oz. (240 mL) of cold or room temperature beverage or 4 oz. to 6 oz. of food immediately before ingestion
- Patients weighing 30 to 65 kg (66 to 143 pounds)
- 10 grams per dose orally, twice per day (20 grams per day)
- 2 packets per dose, 4 packets per day
- Mix each dose in 8 oz. (240 mL) of cold or room temperature beverage or 4 oz. to 6 oz. of food immediately before ingestion
- Patients weighing greater than 65 kg (greater than 143 pounds)
- 15 grams per dose orally, twice per day (30 grams per day)
- 3 packets per dose, 6 packets per day
- Mix each dose in 8 oz. (240 mL) of cold or room temperature beverage or 4 oz. to 6 oz. of food immediately before ingestion
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION 5 grams to 15 grams orally, twice daily based on body weight. (2) Each dose of L-glutamine oral powder should be mixed in 8 oz. (240 mL) of cold or room temperature beverage or 4 oz. to 6 oz. of food before ingestion. (2) 2.1 Dosage Administer L-glutamine oral powder orally, twice per day at the dose based on body weight according to Table 1. Table 1. Recommended Dosing Weight in kilograms Weight in pounds Per dose in grams Per day in grams Packets per dose Packets per day less than 30 less than 66 5 10 1 2 30 to 65 66 to 143 10 20 2 4 greater than 65 greater than 143 15 30 3 6 2.2 Preparation of Product Mix L-glutamine oral powder immediately before ingestion with 8 oz. (240 mL) of cold or room temperature beverage, such as water, milk or apple juice, or 4 oz. to 6 oz. of food such as applesauce or yogurt. Complete dissolution is not required prior to administration.
2.1 Dosage Administer L-glutamine oral powder orally, twice per day at the dose based on body weight according to Table 1. Table 1. Recommended Dosing Weight in kilograms Weight in pounds Per dose in grams Per day in grams Packets per dose Packets per day less than 30 less than 66 5 10 1 2 30 to 65 66 to 143 10 20 2 4 greater than 65 greater than 143 15 30 3 6
2.2 Preparation of Product Mix L-glutamine oral powder immediately before ingestion with 8 oz. (240 mL) of cold or room temperature beverage, such as water, milk or apple juice, or 4 oz. to 6 oz. of food such as applesauce or yogurt. Complete dissolution is not required prior to administration.
Read the full Dosage and Administration section on DailyMed →
L-glutamine side effects
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The most common side effects in clinical trials were:
Common side effects
- Constipation
- Nausea
- Headache
- Stomach (abdominal) pain
- Cough
- Pain in arms or legs
- Back pain
- Chest pain
When to get medical help
- Call your doctor if side effects are severe, don't go away, or are hard to tolerate.
- Get medical help right away for chest pain or any symptom that worries you, since chest pain can also be a sign of sickle cell complications.
- Report any suspected side effect to your doctor, or to FDA MedWatch at 1-800-FDA-1088.
Few people (2.7%) stopped treatment because of side effects. Contact your doctor about any severe or lasting symptoms.
L-glutamine warnings and precautions
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- No contraindications and no boxed warning are listed.
- Deaths occurred in 3 of 187 people on L-glutamine and none on placebo in trials. None were considered related to the medicine.
- Many side effects, such as chest pain and back pain, also occur with sickle cell disease itself, so report new or worsening symptoms.
L-glutamine interactions
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No drug interaction studies have been done.
- Tell your pharmacist about all your medicines and supplements so they can check for problems.
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking L-glutamine
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- Pregnancy: no data are available on risk.
- Breastfeeding: no data on milk or effects on the baby. Your doctor will weigh the benefits and risks.
- Children: established for ages 5 and older, not under 5.
- Older adults: not enough people 65+ were studied. Dosing is usually cautious.
- Kidney or liver impairment: not studied.
L-glutamine overdose
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In animal studies, very large single oral doses were lethal. If an overdose happens, supportive care (treating symptoms and keeping the person stable) is recommended. Get medical help right away.
What L-glutamine does in the body
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In living subjects, L-glutamine supplementation improved NAD redox potential. This is a measure of how well red blood cells handle oxidative stress.
How your body processes L-glutamine
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After a dose by mouth, blood levels peak in about 30 minutes to 1 hour. Food does not significantly change levels. Levels don't build up with twice-daily dosing.
L-glutamine is broken down by normal metabolism, which is its main route of removal. Less than 0.3% was found in urine after IV infusion. Its half-life after an IV dose was about one hour. Body weight affects exposure, which is why dosing is weight-based.
How to store L-glutamine
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Store at 20º to 25ºC (68º to 77ºF); excursions permitted to 15° to 30°C (59° to 86°F) ; away from direct sunlight.
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Supplements & herbs that interact with L-glutamine
19 supplements and herbal products have documented interactions with L-glutamine in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 1
- Moderate · 9
- Minor · 9
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Nutrient depletion considerations
L-glutamine has been associated with lower levels of 3 nutrients in the clinical literature. This does not mean a deficiency will occur — it means these may be worth discussing with your pharmacist or healthcare provider, especially with long-term use.
Educational information from a licensed clinical database (Natural Medicines) — not medical advice. Do not start or stop medications or supplements without professional guidance.
L-glutamine: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about L-glutamine — the kind of thing our pharmacy team would talk through with you at the counter.
What is L-glutamine for?
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How do I take it?
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What side effects should I expect?
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Does it interact with my other medicines?
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Can I take it if I'm pregnant or breastfeeding?
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Is it safe for my child?
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Is L-glutamine available over the counter?
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When was L-glutamine first available?
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Who makes L-glutamine?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about L-glutamine on HelloPharmacist
L-glutamine forms and strengths (how it comes)
L-glutamine is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see L-glutamine inactive ingredients by manufacturer.
Oral solution
L-glutamine on the U.S. market: products, makers and brands
How L-glutamine appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
3 companies list 3 L-glutamine product records with the FDA, mostly as oral solution; the earliest marketing or approval year on record is 2004. Brand names on the directory include Endari; the rest are generics.
Also listed with the FDA, not a patient dose form: Powder (4) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
How widely L-glutamine is used (Medicaid data)
A general measure of how commonly L-glutamine is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely L-glutamine is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is L-glutamine prescribed? Of the 1,601 medications we measure, L-glutamine ranks #1,167 by Medicaid prescriptions — more than 27% of them.
Utilization by L-glutamine product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
glutamine 5000 MG Powder for Oral Solution
Summed across the 2 of 7 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1869684
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of L-glutamine, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 2 of 7 listed L-glutamine NDCs with Medicaid activity.
Compare L-glutamine products
A representative set of FDA-listed product records for L-glutamine — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Oral solution | ||||
| 5 g | Oral | ANI Pharmaceuticals, Inc. | ANDA | View NDC → |
| 5 g | Oral | Camber Pharmaceuticals, Inc. | ANDA | View NDC → |
| 5 g | Oral | Renova Pharmaceuticals LLC | ANDA | View NDC → |
Showing 3 of 3 products — FDA National Drug Code Directory. See every product, package size and price: browse all 3 L-glutamine NDCs →
L-glutamine side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for L-glutamine — a signal of what to watch for, not proof the drug caused it.
The effects most often named in FDA reports that mention L-glutamine are nausea, sickle cell anaemia with crisis, fatigue; about 58% of the reports were classed as serious. These are voluntary reports, so they show what people report, not how often it happens.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists L-glutamine in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
L-glutamine FDA approval history
How L-glutamine went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
L-glutamine was first approved by the FDA in 2004 (Brand: NUTRESTORE · Emmaus Medcl); the first generic version was approved in 2024. It remains available in U.S. pharmacies today.
Source: Drugs@FDA.
L-glutamine recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list no L-glutamine recalls since July 2021.
✅No L-glutamine recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 4885 3 dose forms · 4 strengths
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Dose form (SCDF) Oral Capsule RxCUI 372329No current FDA listingClinical drug / strength (SCD) 500 MGRxCUI 199866750 MGRxCUI 579958 -
Dose form (SCDF) Oral Tablet RxCUI 375103No current FDA listingClinical drug / strength (SCD) 500 MGRxCUI 199153 -
Dose form (SCDF) Powder for Oral Solution RxCUI 1869683In current FDA listingsClinical drug / strength (SCD) 5000 MGRxCUI 1869684
Look up RxCUI 4885 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
L-glutamine supply and shortage status
Whether L-glutamine is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
L-glutamine brand names
L-glutamine is sold under one brand name in the FDA directory — Endari. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes L-glutamine: manufacturers and labelers
3 companies list L-glutamine products with the FDA. By number of product records, the largest are ANI Pharmaceuticals, Inc., Camber Pharmaceuticals, Inc., Renova Pharmaceuticals LLC. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
L-glutamine drug class (RxNorm)
L-glutamine belongs to the Amino Acid class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this L-glutamine page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Renova Pharmaceuticals LLC is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →