What Is Glutamine (Endari)? Uses, Dosage, and What You Need to Know in 2026

Glutamine, sold under the brand name Endari, is an FDA-approved prescription medication for sickle cell disease (SCD). While glutamine is an amino acid your body naturally produces and you get from food, pharmaceutical-grade prescription Glutamine is specifically formulated to reduce the serious complications of sickle cell disease — a role that regular food or over-the-counter supplements cannot reliably fill.

This guide covers everything you need to know about Glutamine (Endari) — what it is, what it treats, how to take it, and key facts for 2026.

What Is Glutamine (Endari)?

Glutamine is an amino acid — one of the 20 building blocks of protein. It's the most abundant amino acid in the human body and plays important roles in immune function, gut health, and cellular energy production. While the body normally produces enough glutamine, certain medical conditions — including sickle cell disease — create an increased demand that the body cannot meet on its own.

Prescription Glutamine (Endari) is pharmaceutical-grade L-glutamine oral powder, formulated specifically for medical use. It comes in precisely measured 5-gram foil packets and is available only by prescription through specialty pharmacies.

What Is Glutamine Approved to Treat?

The FDA approved Glutamine (Endari) in July 2017 for one specific indication:

Reducing the acute complications of sickle cell disease in adults and pediatric patients 5 years of age and older.

This was a landmark approval. It was the first new treatment for sickle cell disease in nearly 20 years — and the first treatment ever approved specifically for children with SCD. Prior to Endari, hydroxyurea (approved in 1998) was the only FDA-approved oral medication for SCD.

Acute complications of SCD that Glutamine helps reduce include:

Vaso-occlusive crises (VOCs) — painful episodes caused by sickled red blood cells blocking small blood vessels

Hospitalizations due to sickle cell pain crises

Acute chest syndrome episodes (fewer episodes were seen in the Glutamine group in trials)

What Forms Does Glutamine Come In?

Prescription Glutamine for sickle cell disease comes in one form: oral powder in individual 5-gram foil packets. Each packet contains white crystalline powder that must be mixed with a liquid or soft food before taking.

It is NOT available as a tablet, capsule, liquid, or injection for this indication. The only other forms of L-glutamine available (OTC supplements) are not FDA-approved for sickle cell disease.

Glutamine Dosage: How Much Do You Take?

The dose of Glutamine is based on your body weight. The recommended dose is 0.3 grams per kilogram of body weight, taken twice daily:

Under 30 kg (66 lbs): 5 grams (1 packet) twice daily = 10 g/day

30 to 65 kg (66–143 lbs): 10 grams (2 packets) twice daily = 20 g/day

Over 65 kg (143 lbs): 15 grams (3 packets) twice daily = 30 g/day (maximum dose)

These doses are significantly higher than any OTC glutamine supplement provides — which is one reason why supplements cannot substitute for prescription Endari.

How to Take Glutamine (Endari)

Measure or take the correct number of 5-gram packets for your dose

Pour the powder into 8 oz (240 mL) of a cold or room-temperature beverage (water, milk, apple juice) OR into 4–6 oz of cold soft food (yogurt, applesauce)

Stir to mix (complete dissolution is not required)

Drink or eat it immediately — do not prepare in advance

⚠️ Important: Do NOT mix with hot food or liquid — heat can degrade the medication

Does Glutamine Work? What the Clinical Evidence Shows

The FDA approval was based on a Phase 3 randomized, double-blind, placebo-controlled trial involving 230 patients (ages 5–58) with sickle cell anemia or sickle β0-thalassemia. Results after 48 weeks:

Median number of pain crises: 3 in the Glutamine group vs. 4 in placebo (statistically significant, p=0.005)

Hospitalizations: 33% fewer in the Glutamine group compared to placebo

Acute chest syndrome: fewer episodes in the Glutamine group

Key Facts at a Glance

Brand name: Endari (generic available since July 2024)

Drug class: Amino acid / antioxidant precursor

FDA approval: July 2017, for ages 5+

Controlled substance: No

Pharmacy type: Specialty pharmacy only

Cash price: ~$3,200+ per 30-day supply retail; ~$1,013 with GoodRx coupon

Learn more about how Glutamine works at a molecular level. Ready to find Glutamine at a pharmacy near you? Try medfinder.