Glutamine is a nonessential amino acid that becomes a conditionally essential amino acid under specific circumstances like illness or injury. It is one of the building blocks of protein and the most abundant amino acid in the human body.
Even though glutamine supplements are a popular dietary supplement today due to the amino acid’s outstanding health benefits, there are some glutamine side effects and risks to be aware of. From nausea to a fast heartbeat, incorrectly supplementing with glutamine can cause side effects that could otherwise be preventable.
Continue reading to learn more about the glutamine side effects and how to prevent them!
Potential Glutamine Side Effects & Risks

So, is L-glutamine safe to take as a supplement? There are many great health benefits associated with the amino acid glutamine. Still, like with any supplement or medication, there are acute complications that can arise with high intakes or conflicting medical conditions or medications.
Potential Glutamine Side Effects:
- Nausea
- Heartburn
- Bloating
- Dizziness
- Stomach pain
- Fast heartbeat
- Blood in urine
- Changes in skin color
It is crucial to consult with a medical professional before taking a supplement to avoid any adverse impacts on one’s health. If these side effects or risks arise, immediately cease glutamine supplementation. Most of these side effects will disappear once supplementation has ended, but others may require medical attention.
The Role of Glutamine
Glutamine is crucial for the immune system, muscle gain and recovery, intestinal health, and overall quality of life, and it is responsible for removing excess ammonia, a common waste product, from the human body. Because of the many health benefits of glutamine, there are many uses for this nonessential amino acid that becomes a conditionally essential amino acid under times of stress or critical illness.
Taking glutamine supplements with growth hormone while consuming an optimal diet has been shown by clinical studies to effectively reduce parenteral nutrition for patients who are receiving help to treat short bowel syndrome. Individuals with glutamine deficiency can also benefit from supplementation of glutamine to restore depleted stores, reduce inflammation, speed up recovery, and boost the immune system.
Situations where glutamine amino acid is beneficial include:
- Sickle cell disease
- Short bowel syndrome
- Critically ill patients
- Cancer
- Bone marrow transplant
- Leaky gut syndrome
- Inflammatory bowel disease (IBS)
- Crohn’s disease
Who Should Not Take Glutamine
There are instances where taking glutamine can produce life-threatening symptoms for individuals who have pre-existing medical conditions or are taking medications that can be negatively affected by the addition of glutamine supplementation.
It’s crucial for those with medical conditions to follow the diet and medication plan provided with their doctor’s instructions. Before beginning glutamine supplementation, it is vital to first speak with your doctor to ensure that it will not cause any adverse complications to your health.
Contraindications for glutamine supplementation:
- Pregnant or breastfeeding
- Children
- Bipolar Disease
- Liver Disease
- Kidney Disease
- Seizures
- MSG Sensitivity
How to Take L-Glutamine Supplements—Dosing & Supplement Form

From dosing to supplement form, it’s important to know how to take this amino acid to receive the most benefits.
As a precautionary measure, please call your doctor or nutrition counselor to consult them first before beginning glutamine supplementation. Keep reading to learn more about dosing and supplement form for maximum benefits and lowered risk of side effects for glutamine!
Dosing
Taking anywhere from 5-20 grams a day is recommended for glutamine supplementation dosing. Glutamine is typically taken in multiple doses throughout the day, usually at 5 grams each, so it is easy to adjust the dosage depending on your goals and the effectiveness of a lower or higher dosage.
One study examined that 20-30 grams of glutamine daily had no negative health repercussions for a healthy adult. When taking over-the-counter glutamine supplements, ensure that you follow the instructions on the label, as dosages for oral powder and capsules may differ per brand.
Supplement Form
There are two main types of glutamine supplements: glutamine powder and capsules.
For the quickest-acting benefits, glutamine powder is ideal. The powder is mixed with a liquid, and the human body quickly absorbs liquids resulting in access to the benefits of this amino acid faster. A capsule or tablet glutamine supplement is still effective. Still, the body will take time to digest the capsule before the benefits of the amino acid can come into full effect.