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Apr 18, 2024

Glutamine: Nutrition and More

Glutamine is the most abundant amino acid (protein building block) in the blood. It's an important energy source for cells that multiply quickly, like those of the gastrointestinal (GI) tract and

Glutamine is the most abundant amino acid (protein building block) in the blood. It's an important energy source for cells that multiply quickly, like those of the gastrointestinal (GI) tract and immune system. It is also a source of nitrogen for many reactions in the body.

Glutamine is available as two prescription medicines that have been approved by the Food and Drug Administration (FDA):

They are both glutamine powders that require a prescription from a healthcare provider.

Glutamine is also found in foods, and sold over-the-counter (OTC) as a dietary supplement which may also be called L-glutamine.

This article focuses on glutamine's uses as a dietary supplement, nutrition, along with safety tips to think about before adding it to your daily regimen.

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian (RD) or registered dietitian nutritionist (RDN), pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Besides its research and approval for sickle cell disease and short bowel syndrome, glutamine has been studied for several other uses, including athletic performance and burn healing.

And as with most dietary supplements, the evidence is mixed.

Here's the latest research about glutamine's effects.

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When the body is under stress (due to serious injuries, burns, or infections), it may need more glutamine than it can produce.

Glutamine supplementation plays a role in several aspects of wound healing, according to a review of 39 clinical trials.

Trials showed supplementing with glutamine can shorten the length of hospital stays. It may also decrease markers of inflammation, like interleukin-6 (IL-6) and C-reactive protein (CRP).

Another review showed that glutamine supplementation was associated with faster healing in burn patients.

Glutamine plays several roles in the GI tract. For instance, it protects the mucosal barrier of the intestines and can prevent toxins from reaching the bloodstream.

Glutamine has been researched for various digestive diseases. However, there's little evidence it's beneficial.

One possible exception is severe acute pancreatitis (sudden pancreas inflammation). One review determined that giving glutamine in addition to nutrition via a feeding tube lowered risks of the following:

According to a review, glutamine only slightly improved the following in people with inflammatory bowel disease (IBD):

This was true across delivery methods—including orally (by mouth), intravenously (through an IV), or enterally (through a feeding tube)—for people in hospital and outpatient settings. However, the researchers suggested it was unclear whether the benefits were from glutamine alone.

It's also been studied in infants with severe GI diseases, such as the following:

Theoretically, glutamine can help repair injured tissue. However, it did not affect the survival or infection rates of the infants.

Oral mucositis (swelling and mouth ulcers) is a common complication of cancer treatments.

People with head and neck cancer treated with radiation plus glutamine had less severe mouth sores than those who didn't receive glutamine, even though the likelihood of developing mucositis was the same. People who took glutamine also had lower rates of opioid pain medications and tube feeding.

Similar results were seen when glutamine supplementation was studied for people with cancer treated with either chemotherapy or radiation. Glutamine didn't reduce the incidence of oral mucositis but decreased its severity.

But not all data are promising. For instance, a study in pediatric cancer patients showed that glutamine supplementation did not lower the likelihood or severity of mouth sores.

And a review concluded that there wasn't enough evidence to recommend glutamine for preventing or treating oral mucositis.

Because glutamine levels may be depleted in cases of severe illness, several studies have examined its effects on people hospitalized with these conditions.

Glutamine is typically given intravenously or enterally within a hospital setting.

The results are mixed, but there appears to be only limited benefit overall. Studies have shown that only about 1 in 3 patients admitted to the intensive care unit (ICU) have low glutamine levels.

Glutamine supplementation shouldn't routinely be started for critically ill patients except those with severe burns.

Some people take glutamine to enhance exercise performance, but little evidence supports this claim.

In a review of 25 clinical trials, glutamine did not affect athletic performance, body composition, or the immune system.

Of note, it may help with weight loss, according to the review.

Most adults consume between 3 and 6 g of glutamine daily from foods containing protein.

Here are the amounts of glutamine found in a 3.5-ounce serving of these common foods:

Glutamine is also available as an OTC supplement in tablet, capsule, liquid, and powder forms. It's also an ingredient in some protein supplements.

Side effects that were seen in trials of the prescription product Endari (L-glutamine powder) included:

These side effects were seen in up to 20% of people with sickle cell disease who used prescription glutamine.

There isn't much data on side effects from OTC glutamine supplements, though they are likely similar to those listed above.

Take glutamine at the recommended dose for best results, and contact your healthcare provider or pharmacist if you experience side effects.

Do keep the following precautions in mind when using glutamine:

Glutamine may interact with the following medications:

It is essential to carefully read a supplement's ingredients list and nutrition facts panel to know which ingredients and how much of each ingredient is included. Please review the supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.

There is no recommended dosage for oral glutamine supplements.

Studies have used the following glutamine doses:

The FDA has approved the following recommended doses for prescription medications that contain glutamine:

Adult glutamine doses of up to about 30 grams a day seem to be well-tolerated.

Dietary supplements are not regulated in the same way drugs are in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. Choose a supplement tested by a trusted third party, such as the U.S. Pharmacopeia (USP), ConsumerLab.com, or NSF.org, whenever possible. However, even supplements that are third-party tested are not necessarily safe for all or effective in general. Therefore, talking to your healthcare provider about any supplements you plan to take and checking in about potential interactions with other supplements or medications is important.

Glutamine is an amino acid made in the body. Most healthy people consume all they need through protein-containing foods, such as beef, tofu, and eggs.

But sometimes, supplementation is warranted, typically under the supervision of a healthcare provider. Some examples of people who might benefit from glutamine are those with severe burns or those undergoing cancer treatment.

The FDA has approved prescription products Endari and Nutrestore following rigorous studies. However, the agency has not approved OTC glutamine supplements.

If you decide to try glutamine, purchase a product that has been third-party tested by USP, ConsumerLab, or NSF if possible.

Certification for a company does not mean the product is safe or effective. Instead, it offers assurance that the ingredients match what is listed on the label and that the product is free of contaminants.

Glutamine is an amino acid that's made in the body and also found in some protein-containing foods. It's available as an OTC dietary supplement and two FDA-approved prescription medications.

Glutamine is an energy source for cells that rapidly divide, like those of the GI tract and immune system. It also supplies nitrogen needed in many reactions in the body.

Though the evidence is still limited, glutamine may promote wound healing for people with severe burns. It may also improve outcomes of people with acute pancreatitis, or cancer patients with mouth sores.

Yes. Glutamine can be given intravenously (IV), enterally (through a feeding tube), or orally (by mouth). OTC dietary supplements are available as powders, capsules, and tablets and often labeled as L-glutamine.

There's not enough evidence to recommend glutamine for this use.

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By Megan Nunn, PharmDMegan Nunn, PharmD, is a community pharmacist in Tennessee with over twelve years of experience in medication counseling and immunization.