Glutamine: Benefits, Uses and Side Effects

Glutamine is an important amino acid that has many functions within the body.

It is a building block of proteins and an essential part of the immune system.

Additionally, glutamine plays a special role in gut health.

Your body naturally produces this amino acid, and it is also found in many foods. Still, you may need extra glutamine from supplements for optimal health.

This article explains why glutamine is important and discusses the benefits of glutamine supplementation as well as possible side effects.

What is Glutamine?

Glutamine is an amino acid. Amino acids are molecules that play many roles in the body. Their main purpose is to serve as building blocks of proteins.

Proteins are essential for organs. They also perform other functions, such as transporting substances through the blood and fighting off harmful viruses and bacteria.

Like many other amino acids, it exists in two different forms: L-glutamine and D-glutamine. These forms are nearly identical but have a slightly different molecular arrangement.

The form found in foods and supplements is L-glutamine. Some supplements list it as L-glutamine, but others just use the broader term glutamine.

While L-glutamine is used to make proteins and perform other functions, D-glutamine appears to be relatively unimportant in living organisms.

L-glutamine can be produced naturally in your body. It is the most abundant amino acid in blood and other bodily fluids.

However, sometimes your body's need for glutamine exceeds its ability to produce it. Therefore, it is considered a conditionally essential amino acid, which means that it must be obtained from the diet under certain conditions, such as injury or disease.

Additionally, glutamine is an important molecule for the immune system and gut health.

What are the benefits of Glutamine?

Role on the Immune System

One of the most important functions of glutamine is its role in the immune system.

It is an essential fuel source for immune cells, including white blood cells and some intestinal cells.

However, its blood levels may decrease following major injuries, burns or surgery.

If the body's need for glutamine exceeds its ability to produce it, the body can break down protein stores, such as muscle, to release more of this amino acid.

Additionally, immune system function can be compromised when insufficient amounts of glutamine are available.

For these reasons, high protein diets, high glutamine diets, or glutamine supplements are often prescribed after major injuries such as burns.

Studies have also reported that glutamine supplements can improve health, decrease infections, and lead to shorter hospital stays after surgery.

Additionally, they have been shown to improve survival and reduce medical costs in critically ill patients.

Other studies have shown that glutamine supplementation can also improve immune function in animals infected with bacteria or viruses.

Role on the Intestines

The benefits of glutamine for the immune system are linked to its role in gut health.

In the human body, the intestines are considered the largest part of the immune system. This is due to the many intestinal cells with immune functions, as well as the millions of bacteria that live in your intestines and impact your immune health.

Glutamine is an important source of energy for intestinal and immune cells.

It also helps maintain the barrier between the inside of your intestines and the rest of your body, protecting you against leaky gut.

This prevents harmful bacteria or toxins from passing from your intestines to the rest of your body.

Due to the gut's major role in the immune system, glutamine may benefit your overall immune health by supporting gut cells.

Role on Muscle Gain and Performance

Because of its role as a building block of protein, some researchers have investigated whether taking glutamine as a supplement improves muscle gain or exercise performance.

In one study, 31 people took glutamine and a placebo for six weeks of resistance training (weight training).

At the end of the study, both groups showed improvement in terms of muscle mass and strength. However, no difference was found between the two groups.

However, some research has reported that glutamine supplements may decrease muscle soreness and improve recovery after intense exercise.

One study found that glutamine or glutamine combined with carbohydrates can help reduce fatigue during two hours of running.

Ultimately, there is no evidence that these supplements provide benefits for muscle gain or strength. There is limited support for other effects, but more research is needed.

It's also important to note that many athletes have high protein intakes in their regular diet, which means they can consume large amounts of glutamine even without a supplement.

Dosage and Side Effects

Since glutamine is an amino acid naturally produced by the body and found in many foods, there is no reason to fear that it is harmful in normal amounts.

It has been estimated that a typical diet may contain 3-6 grams per day, although this amount may vary depending on the types and amounts of food eaten.

Studies of glutamine supplements have used a wide variety of doses, ranging from around 5 grams per day to high doses of around 45 grams per day for six weeks.

Although no negative side effects have been reported with this high dosage, blood markers have not been specifically examined.

Other studies have reported minimal issues with short-term supplementation of up to 14 grams per day.

Overall, short-term supplement use is considered likely safe. However, some scientists have raised concerns about their prolonged use.

Adding glutamine to a normal diet can cause various changes in the way the body absorbs and processes amino acids. However, the long-term effects of these changes are unknown.

Therefore, more information is needed regarding long-term supplementation, especially when high doses are used.

Glutamine supplements may not have the same effects if you follow a meat-based, high-protein diet compared to a vegetarian-based, low-protein diet.

If you follow a low-glutamine vegan diet, you can consume supplements while still receiving a normal daily amount of glutamine overall.

If you decide to take a glutamine supplement, it's probably best to start with a conservative dose of around 5 grams per day.

Our selection of Glutamine