Glutamine: Benefits, Uses, and Side Effects

Glutamine is a nonessential amino acid that serves as a building block for proteins.

It is considered a conditionally essential amino acid, which means it must be obtained from the diet under certain circumstances, such as injury or illness.

It is synthesized from glutamic acid and ammonia and is involved in many metabolic processes.

The two different forms of glutamine include L-glutamine (found in foods and man-made supplements) and D-glutamine (relatively unimportant in humans).

Glutamine supports several functions of the body, including:

• Making proteins for muscle tissues
• Fueling cells that protect the stomach and the intestines (enterocytes)
• Supporting immune system cells
• Helping the liver detoxify foreign substances

Manmade versions or glutamine supplements are available in the form of:

• Capsule
• Tablet
• Powder for solution
• Packet
• Powder for suspension

The body naturally makes glutamine in the muscles, which is transferred by the blood into different organ systems.

Because animal products, such as meat, eggs, and beef, are high in protein, they are the simplest ways to get high amounts of glutamine as well.

However, some plant-based foods have an adequate amount of glutamine, such as wheat, peanuts, corn, tofu, and milk.

The deficiency of glutamine is rare and is often caused by genetic disorders rather than inadequate intake.

Endari (glutamine) is approved by the U.S. Food and Drug Administration as a prescription drug for sickle cell disease.

Other conditions wherein glutamine is possibly effective include:

• Heals burns
• Reduces complications of trauma or critical illness 
• Patients with human immunodeficiency virus or acquired immunodeficiency syndrome absorb food better, which prevents unwanted weight loss
• Faster recovery after surgery
• Glutamine is used in combination with human growth hormone (GH) to treat short bowel syndrome

The amount, dosage, and frequency of glutamine supplements depend on the reason for prescription and the general condition of the patient.

According to an estimate, people consume about three to six grams of glutamine daily in the diet. 

Some clinical studies have speculated that doses of 5 to 45 grams per day for up to six weeks are considered safe with no negative side effects.

Research suggests that glutamine supplements may offer some health benefits, but studies are underway to confirm the potential of glutamine to prevent or treat certain conditions.

1. Improves recovery times and reduces complications
   • It may help people with gut conditions such as Crohn’s disease, celiac disease, and gut inflammation.
2. Boosts immunity
   • It acts directly on gut-associated lymphoid tissue and stimulates overall immune function.
   • Glutamine supplements might help the gut, immune system, and other processes function properly, especially in times of stress, such as trauma, injury, or illness.
   • It is the main fuel source for lymphocytes, and white blood cells that fight infection and diseases.
3. Promotes intestinal health
   • The amino acid helps maintain the intestinal lining, ensuring that the body absorbs the nutrients it needs.
   • It supports overall good health and protects against serious problems, such as leaky gut syndrome.
   • It plays a major role to protect the integrity of the gastrointestinal tract, especially the large intestine.
4. Helps recover muscle
   • Glutamine supplements may act as fitness supplement that promotes muscle gain and fat burn.
   • It may help reduce fatigue and improve exercise recovery.
   • In addition, it may reduce muscle damage and aid in exercise performances.
5. May help ease the effects of cancer treatments, such as muscle wasting, oral inflammation, nausea, vomiting, and diarrhea.
6. Glutamine supplements are linked with shorter hospital stays and lower mortality rates for critically ill patients.
7. Reduces the acute complications of sickle cell disease in adults and children.

1. Long-term impact
   • Excessive intake over time may change the way the body distributes and uses amino acids, which may raise the risk of health problems.
2. Hazardous side effects
   • Side effects are generally mild and might include bloating, nausea, dizziness, heartburn, changes in bowel movements, and stomach pain.
   • In some rare cases, high quantities of glutamine can cause side effects that may require immediate medical attention, including blood in the urine, changes in the skin color, lower back pain, fast heartbeat, dizziness, or rash. 
3. May worsen liver and kidney diseases
   • People with liver and kidney conditions need to be extra cautious before taking a glutamine supplement.
4. Pregnancy
   • There is not enough evidence or conclusive studies to confirm the safety of glutamine in pregnant or breastfeeding women.
   • Do not use glutamine until advised by a medical health professional.