Glutamine is the most abundant amino acid in the human body. It plays a vital role in several critical bodily functions, including immune support and inflammation regulation.

It is considered a conditionally essential amino acid, meaning your body can typically produce enough under normal circumstances. However, in times of illness, injury, or pregnancy, the body's need for glutamine increases and may require external sources.

1. Supports Immune Function

The immune system relies heavily on glutamine to function properly. Certain immune cells, such as T cells, use glutamine at a rapid rate. These cells help defend against infections and diseases, including cancer.

Glutamine supports the production of T cells and cytokines, which are proteins that help the immune system respond to threats. Because of its essential role, the body demands more glutamine during illness or recovery from physical trauma, like surgery.

2. Keeps Your Gut Healthy

Glutamine is also essential for maintaining gut health. It plays a key role in protecting the gut lining, helping prevent harmful bacteria and toxins from entering the bloodstream.

Intestinal cells, known as enterocytes, depend on glutamine as a primary energy source. The digestive system uses a significant amount of the body's glutamine supply, often competing with other organs for it.

Glutamine helps maintain the strength of tight junctions, which are barriers that protect the intestinal lining. When glutamine is low, these barriers can weaken, leading to increased gut permeability, also known as a “leaky gut.”

People with digestive conditions, such as irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD), may benefit from glutamine supplements due to its role in reducing intestinal inflammation.

3. Essential During Critical Illness, Injury, and Pregnancy

In periods of physical stress, such as severe illness or injury, the body’s demand for glutamine rises sharply. This is because white blood cells, which fight infection and aid healing, require glutamine as fuel.

In hospitals, glutamine is often provided through intravenous (IV) lines or feeding tubes to critically ill patients, including those recovering from trauma or surgery. Supplementing glutamine in these cases has been shown to reduce infection rates, shorten hospital stays, and improve recovery.

During pregnancy, glutamine needs also increase to support fetal growth. Because the developing baby requires more glutamine than the mother’s body can typically produce, dietary intake becomes especially important. Eating more protein-rich foods during pregnancy can help meet this increased demand.

How Much Glutamine Do You Need?

The body normally produces between 40 to 80 grams of glutamine daily, which is generally enough for healthy individuals. On average, people consume around 3 to 6 grams of glutamine from food each day.

While the body’s natural production is usually sufficient, during times of stress or illness, additional glutamine may be required to maintain healthy levels.

Good Sources of Glutamine

Glutamine is found in both plant-based and animal-based protein sources. Foods high in glutamine include:

  • Corn: 16.2% of its protein content is glutamine

  • White rice: 11.1%

  • Tofu: 9.1%

  • Milk: 8.1%

  • Beef: 4.8%

  • Eggs: 4.4%

Maintaining a balanced diet with a mix of protein-rich foods helps keep glutamine levels within a healthy range. In specific cases—such as illness, pregnancy, or chronic inflammation—higher protein intake or glutamine supplementation may be needed.

Supplements

In medical settings, glutamine is often administered via IV or feeding tubes for patients who are critically ill or recovering from surgery. Outside of clinical use, glutamine is also a popular supplement among athletes and individuals under physical stress.

Some research indicates that glutamine supplements may help reduce muscle damage from intense exercise and support recovery. They may also be beneficial in reducing inflammation and improving metabolic health in specific populations, including older adults and people recovering from viral infections.

Supplement doses typically range from 2 to 40 grams per day, depending on the need and situation.

Potential Risks and Side Effects

Glutamine supplements are generally considered safe, whether taken orally or delivered intravenously. Most studies show no serious side effects, even at high doses.

However, long-term safety data is limited. While doses as high as 45 grams per day have not shown harmful effects, the generally recommended maximum for long-term use is around 14 grams per day.

It’s always best to consult with a healthcare provider before starting glutamine supplements, especially if you have underlying health conditions or are on medication.

Interactions

Although glutamine is widely considered safe, it can interact with certain medications:

  • Lactulose: Used to treat liver disease by lowering ammonia levels. Glutamine may reduce its effectiveness.

  • Methotrexate: A drug for cancer and autoimmune diseases. Glutamine might enhance its effects, so medical supervision is advised.

Always speak with your healthcare provider if you’re taking medication and considering glutamine supplements.

A Quick Review

Glutamine is a key amino acid involved in immunity, digestion, and stress recovery. While the body usually produces enough on its own, special conditions such as illness, trauma, or pregnancy can increase the body’s demand.

You can maintain healthy levels through a balanced, protein-rich diet. In specific cases, supplementation may offer additional support for gut health, immune response, or exercise recovery.