The Health Benefits of L-Glutamine

May improve gut health and wound healing

Female runner in park
Matthew Leete/Photodisc/Getty Images

L-glutamine is the most plentiful amino acid in the body. It's involved in protein synthesis and serves as fuel for the immune system. Most people benefit from taking glutamine when their immune system is weakened or for healing a major wound like a burn or after surgery.

Though l-glutamine is found in food and supplements, it's unnecessary to take supplemental l-glutamine because it's a non-essential amino acid. That means that your body can make it on its own.

Glutamine also used to be a major mainstay for bodybuilders and athletes for building muscle and reducing recovery times. But taking this supplement has since been abandoned because there's no solid research backing this up today. Here is what you need to know about l-glutamine.

Health Benefits

Years ago glutamine was almost considered a conditionally essential amino acid only for those who are critically ill or injured, such as in the case for burn victims or someone who was physically stressed and at risk of muscle and tissue breakdown. In these situations, supplementing with glutamine could help reduce healing time and would be of benefit.

L-glutamine is also occasionally used to alleviate some of the side effects of chemotherapy. It also has been used for decades for health and exercise purposes in dietary supplements, though many of these claims are unsubstantiated or exaggerated. Here are some potential benefits of l-glutamine.

Immune System Support

Glutamine is important for the immune system as it helps it to function optimally. People who are critically ill or who have experienced severe physical trauma have low glutamine levels due to either a reduction in skeletal glutamine production or cells using up the body's stored glutamine more rapidly due to the trauma.

For that reason, supplementing with l-glutamine could help improve immune system function and speed recovery. Specifically for burn patients, supplementing with glutamine can help maintain healthy immune function, improve wound healing, and shorten hospital stay. In fact, an older study a 2009 study from India reported that the enteral delivery of L-glutamine reduced bacterial complications as well as hospital stays by almost 17 days compared to a control group.

For healthy individuals, the benefits of glutamine for immune function just aren't there. In that sense, if you're not immunocompromised, critically ill, or recovering from surgery, taking a daily glutamine supplement to improve your health is largely a waste of money.

We've tried, tested, and reviewed the best immune supporting supplements. If you're in the market for additional immune support, explore which option may be best for you.

Muscle Building, Fat Loss, and Recovery

Much to the bodybuilding community's dismay, l-glutamine does not offer the muscle-building and fat loss benefits it was once believed to provide. Though scientists continue to look into these claims, the existing research doesn't support them.

For instance, one study examined the effects of glutamine supplementation combined with resistance training in young adults, ages 18 to 24, and found that there were no significant differences between the group who took glutamine and the placebo group. Both groups experienced similar muscle and strength gains.

When it comes to weight loss, several studies support the claim.

This six-week study observed sixty-six patients with type 2 diabetes, They were split into two groups and instructed to take either 30 grams per day of glutamine, or they received a placebo. The group that received glutamine experienced improved cardiovascular risk factors and body composition.

And this study demonstrated that taking glutamine for 4 weeks results in reductions in body weight and waist circumference.

On the other hand, several studies have found the opposite to be true, that glutamine supplementation has no effect on weight loss and body composition. Research is ongoing to determine whether L-glutamine supplementation has positive effects for building muscle and losing weight.

All is not lost for people hoping to reap some sort of athletic benefits from L-glutamine supplementation. Several studies have shown that supplementing with L-glutamine once per day can reduce muscle recovery time and soreness after a tough workout.

In a sense, L-glutamine may help with athletic performance by delaying fatigue. If you're not fatigued, you're able to perform better in the gym and on the field.

Chemotherapy Side Effects

Glutamine may play a pivotal role in improving the quality of life for cancer patients undergoing chemotherapy. In fact, symptoms associated with chemotherapy may be less severe with a lower dose and after treatment.

Chemotherapy often breaks down tissue in the intestinal lining causing mouth and throat sores, called mucositis. Some studies report a reduction in painful mucosal symptoms and ulceration associated with radiation and chemotherapy treatment.

Conversely, other studies have found marginal effects of oral L-glutamine supplementation on mucositis.Though it may have the potential to reduce the degree of pain and discomfort, further research is needed.

Possible Side Effects

L-glutamine is safe for human consumption and does not generally cause significant side effects even at doses up to 40 grams per day. More than that and you may experience mild symptoms such as bloating, gas, nausea, dizziness, heartburn, or stomach upset.

With that said, there have been few studies investigating the long-term effects of l-glutamine supplements or at which doses l-glutamine may cause toxicity. There is evidence, albeit slight, that l-glutamine supplements may trigger seizures in people on anti-convulsant medications. Because l-glutamine is metabolized by the liver, it may need to be avoided in people with severe liver disease.

Due to the lack of research, it is best to avoid l-glutamine during pregnancy or while breastfeeding. While l-glutamine has been used safely in infants and children, it should only be prescribed under the supervision of a pediatrician.

Dosage and Preparation

Your l-glutamine requirements are generally fulfilled through the foods you eat each day. However, if you plan to use a supplement form of l-glutamine, 3 to 6 grams per day is considered safe.

According to an older report in Regulatory Toxicology and Pharmacology, 14 grams of supplemental l-glutamine is safe for healthy adults and no more than 0.7 grams per day per kilogram of body weight in children.

L-glutamine supplements are available in powder, oral capsule, and oral tablet form. Generally, it can be found at your local health food stores, pharmacies, grocery stores, and online.

What to Look For

Because supplement manufacturers in the United States aren't required to put their products through rigorous testing and verification processes, it can be difficult to know whether the product you're purchasing is what it says it is. For that reason, look for brands that voluntarily submit their products for inspection by an independent certifying body like the U.S. Pharmacopeia (USP), ConsumerLab, or NSF International.

Choosing products that display the certifications mentioned above can help ensure you're getting the highest quality and safety standards. If you are vegan or vegetarian, look for l-glutamine supplements made from fermented plant-based materials (usually beets).

Foods Higher in L-Glutamine

To get more l-glutamine in your diet, look for these foods the next time you go to the grocery store:

  • Beef: 1.2 grams per 4-ounce serving
  • Eggs: 0.6 grams per two eggs
  • Tofu: 0.6 grams per 3.5-ounce serving
  • Corn: 0.4 grams per half-cup serving
  • Milk: 0.3 grams per half-cup serving
  • White rice: 0.3 grams per half-cup serving

Frequently Asked Questions

  • Can I get enough l-glutamine from food?

    Yes, you can get plenty of l-glutamine from your diet. Because l-glutamine is an amino acid, choosing high protein foods will help ensure you're getting more than your fair share.

  • When should I take l-glutamine?

    You can take l-glutamine any time of the day. If using it to improve workouts and reduce the onset of fatigue, try using it 30 minutes prior to your workout, during your workout, and/or immediately following a strenuous workout.

  • How much l-glutamine should I take for leaky gut?

    Glutamine is involved in the health of the intestinal lining. L-glutamine deficiency is highly unlikely however reduced glutamine due to chronic illness or trauma is possible and could result in diarrhea or "leaky gut." For that reason, supplementing with l-glutamine may be helpful.

    Dissolve 10 to 15 grams of l-glutamine powder in water; take 1 hour before a meal in the morning and evening daily.

  • How do I take L-glutamine for sugar cravings?

    The idea is that L-glutamine is an amino acid, amino acids are building blocks for protein, and protein helps keep you full and satisfied. So if you take L-glutamine you'll be fuller for longer and have fewer sugar cravings. Unfortunately, there isn't any research supporting that L-glutamine will help with sugar cravings.

  • Does l-glutamine help with alcohol cravings?

    Glutamine production is disturbed when someone drinks alcohol. Once alcohol is out of the system, the body begins producing glutamine again. For alcoholics, discontinuing the use of alcohol leads to alcohol withdrawals of which cause significant undesirable symptoms. It's believed that supplementing with L-glutamine can help reduce symptoms of alcohol withdrawals, however, more research is needed.

  • What is the difference between l-glutamine and glutamine?

    There is little difference between l-glutamine and glutamine and the two terms are often used interchangeably. Glutamine is an amino acid and l-glutamine is an isomer of glutamine with a slightly different chemical structure. L-glutamine is the type found in food, supplements, and the human body.

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Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Shoshana Pritzker RD, CDN, CSSD, CISSN
Shoshana Pritzker RD, CDN is a sports and pediatric dietitian, the owner of Nutrition by Shoshana, and is the author of "Carb Cycling for Weight Loss." Shoshana received her B.S in dietetics and nutrition from Florida International University. She's been writing and creating content in the health, nutrition, and fitness space for over 15 years and is regularly featured in Oxygen Magazine,, and more.