L-Glutamine for Gut Health: Unsung Hero or One to Avoid?

  • By Performance Lab
  • 6 minute read
L-Glutamine for Gut Health: Unsung Hero or One to Avoid?

When it comes to health, most people look at markers like cholesterol, triglycerides, glucose, and other typical markers of chronic disease, but how many people think twice about looking at the health of their gut?

Where gut health is concerned, maintaining the integrity of the intestinal epithelium (aka the gut lining) is essential. The gut lining cells play several vital roles: they support digestion and nutrient absorption, inhibit bacteria and toxins from entering the GI tract, and more.

Essentially, the gut lining is your gatekeeper, allowing certain things through and preventing others. The result? A healthy gut environment promotes health.

But if epithelial cells become damaged, leading to hyperpermeability or “leaky gut,” they can’t do their job, and bacteria sneak through, leading to disastrous effects, including systemic inflammation.

While there are plenty of factors influencing gut health and integrity, there's one supplement that shines: L-glutamine. It’s an essential amino acid to support a healthy gut lining.

This article will cover the basics of L-glutamine for gut health and even give you our best recommendation for a gut health supplement!

What is L-Glutamine?

If you’re not familiar with L-glutamine, let’s start with the basics.

Glutamine is a conditionally essential amino acid—it becomes an essential amino acid under certain conditions, but your body can produce some.

It's one of the 20 naturally occurring amino acids (9 essential and 11 non-essential amino acids) found in animal proteins. As the most abundant amino acid in the bloodstream, glutamine makes up about 30-35% of the amino acid nitrogen in your blood 1.

Generally speaking, most people get enough glutamine through diet (especially with protein-rich foods) and the body’s natural production, but there are certain circumstances that increase intake needs and supplementation might be needed, either with pure L- glutamine or essential amino acids.

These include 2:

  • Certain disease states
  • Muscle wasting
  • Physical trauma
  • Catabolic states (ex., a bone marrow transplant)

Interestingly, about 60% of skeletal muscle comprises the amino acid, so supplementing with it can also support protein synthesis and naturally balance your pH levels.

But while dietary intake of glutamine might be sufficient for the majority of people, anyone struggling with digestive issues like IBS, celiac disease, Crohn’s, or leaky gut syndrome may be advised to supplement, thanks to glutamine’s role in supporting a healthy intestinal lining and good gut health.

Whenever inflammation is present in the GI tract, you need a lot of energy to fight it, and glutamine provides that energy source for epithelial cells.

Health Benefits of L-Glutamine Supplementation

So, what are the health benefits of taking L-glutamine?

There’s plenty of research showing glutamine supplements have several advantages.

Improves GI and digestive tract health and immune function

One of the primary benefits of L-glutamine is for supporting gut health and digestive processes, but it’s also shown to benefit several GI-related conditions, including 3:

  • Irritable bowel syndrome (IBS)
  • Inflammatory bowel disease (Crohn’s, ulcerative colitis)
  • Diverticulosis
  • Diverticulitis
  • Leaky gut

Studies show that glutamine supplements can support gut health and function via three primary mechanisms 4:

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  • Positively impacts the balance of the gut microbiome
  • Increases the expression of tight junction proteins to maintain the integrity of the intestinal lining
  • Minimizes the inflammatory response during gut lining irritation

On top of that, it’s also been shown to support a healthy immune response, potentially through the link between the gut and the immune system.

A 1999 study published in the Journal of Clinical Immunology found that L-glutamine can normalize the effects of specific immune responses and reduce intestinal inflammation 5.

Other studies find that glutamine helps maintain healthy gut microbiota and reduce the colonization and proliferation of pathogenic bacteria, which may reduce the risk of dysbiosis and associated diseases 6.

May treat leaky gut syndrome

For ages, leaky gut was dismissed by health professionals, but more recently, leaky gut has been recognized as an actual condition.

Increased permeability of the GI tract’s epithelial lining creates an easy pass for bacteria and their products to cross from the lumen into the bloodstream, which elicits an immune response 7.

Although leaky gut can contribute to many issues, it’s the leading cause of autoimmunity. It contributes to thyroid issues like Hashimoto’s disease, arthritis, skin issues like psoriasis, and other health concerns.

Because L-glutamine serves as a major fuel source for cells of the small intestine, it offers benefits for intestinal health and the treatment of leaky gut 8.

Several studies have shown that supplementation with L-glutamine reduces gut permeability from various stressors and helps maintain normal intestinal barrier function 9.

Promotes brain health

Glutamine for brain health? Yep, it’s a thing.

As the precursor amino acid to the neurotransmitter glutamate in the brain, glutamine is a crucial amino acid for supporting cognitive function, and a disruption to the glutamine-glutamate cycle can lead to a host of issues, including 10:

  • Reye’s syndrome
  • Epilepsy
  • Schizophrenia
  • Anxiety and depression
  • Alcoholism
  • Bipolar disorder

May support muscle mass and accelerate exercise recovery

Whether you’re looking to boost your performance, increase metabolism, build muscle mass, or accelerate your recovery, adding an L- glutamine supplement to your stack might be beneficial.

Studies show that because training places a lot of stress on the body, muscles and tendons require increased amounts of L-glutamine to sustain function than what’s provided by the average diet.

Following an intense workout, cellular glutamine levels can drop by as much as 50% and serum levels by 30%, which provides a gateway for muscle wasting—but glutamine can prevent this 11.

Some research shows that glutamine supplements can accelerate recovery from intense resistance training sessions and improve muscle hydration, which, in turn, supports better muscle recovery and reduces recovery time 12.

Another study found that athletes supplementing with L-glutamine experienced a faster recovery of peak torque and reduced muscle soreness following eccentric exercise, but this effect may be more pronounced in men than women 13.

Aside from optimal gut health, research suggests that glutamine supplementation may also be beneficial for:

  • Metabolic function
  • Heart health
  • IBS and diarrhea

Simply put, there’s no shortage of benefits associated with L-glutamine supplementation, whether it’s protecting your heart or improving the health of your gut and immune system.

Is L-Glutamine Good For Gut Health?

That said, is glutamine good for gut health? The resounding answer is yes—but supplementation may not be necessary.

A large body of research shows that L-glutamine is beneficial for protecting and maintaining the integrity of the epithelial lining of the gut and supporting cell regrowth and function in the gut.

Still, it appears to be the most beneficial for people struggling with intestinal tract issues, such as those with leaky gut, colitis, Crohn’s, or any other conditions compromising digestive function and health.

However, that doesn’t mean that taking L-glutamine is only recommended for people with pre-existing conditions.

But if you’re looking for a reliable way to maintain a healthy gut—and the health of all other organ systems—there’s an alternative: Performance Lab Prebiotic.

Prebiotic is a 2-in-1 probiotic + soluble fiber support for optimal metabolic and microbiome performance. Because conventional probiotic supplements are unpredictable, they can lead to major gastric distress and inefficacy.

Rather than introduce new bacterial strains into your gut, Prebiotic nourishes those existing with Orafti® Synergy1 (Inulin-FOS from chicory root) for robust growth and health.

As a result, Prebiotic delivers more reliable, natural, and comfortable microbiome support. And with the addition of fiber, Prebiotic also supports digestion, immune function, fat loss, and more.

So, whether you're dealing with an inflammatory bowel disease, a weakened immune system, or struggling with intestinal permeability, adding a probiotic/prebiotic blend to your stack (and perhaps L-glutamine supplements) might be exactly what you need to boost gut function and support optimal health.


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  2. Ziegler TR. Glutamine supplementation in cancer patients receiving bone marrow transplantation and high dose chemotherapy. J Nutr. 2001;131(9 Suppl):2578S-2590S.
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