Often regarded as one of the most underrated sports supplements, L-Glutamine is gaining increased popularity and finally starting to get the attention it deserves. Glutamine is unique in the fact, that not only does it promote ergogenic benefits, but also supports immune system health and digestive health. A growing body of evidence has also suggested that Glutamine can also help gastrointestinal issues like IBD, IBS, and leaky gut.

In this ultimate guide to L-glutamine, we will cover the following topics

• What Is L-Glutamine?
• How Does L-Glutamine Work?
• What Are The Benefits Of L-Glutamine?
• Does L-Glutamine Help IBS?
• Does L-Glutamine Help Chrons Disease?
• Does L-Glutamine Help Leaky Gut?
• What Is The Best L-Glutamine Supplement?
• How Much L-Glutamine Should I Take?
• When Should I Take L-Glutamine?

What Is L-Glutamine? 

L-Glutamine is the most abundant and naturally occurring conditionally essential amino acid in the human body. It makes up approximately 60% of the amino acid pool in your muscle tissue. Nearly 90% of glutamine is produced in the skeletal muscles and it is one of the very few amino acids with such versatility. Glutamine that can cross the blood-brain barrier, giving it the ability to freely enter the brain; it is vital in the process of nitrogen transport between tissues, in acid-base regulation, gluconeogenesis, and as a precursor of nucleotide bases and the antioxidant glutathione.

How Does L-Glutamine Work?

L-Glutamine helps direct the body where and when to place nitrogen atoms in order to rebuild and repair muscle tissue. In order to build muscle mass and strength, you need to maintain a positive nitrogen balance. L-glutamine is a conditionally essential amino acid, meaning that in certain situations, synthesis (production in the body) can be limited.

During intense training periods, your body will actually use and deplete all of its glutamine stores, which inhibits its function and decreases strength, stamina, and lengthens the recovery period. By supplementing L-Glutamine, you’re therefore ensuring your body has an adequate supply of glutamine to maintain a positive nitrogen balance to reduce muscle soreness and protect yourself from workout induced muscle mass breakdown, or DOMS.

L-Glutamine Benefits: Immune System Support

Glutamine is essential for maintaining a healthy immune system. Often overlooked, endurance athletes and powerlifters alike can experience an increased susceptibility to infection, due to weakened immune systems while training. Glutamine is used by white blood cells to produce cytokines, (small proteins released by white blood cells). With an increased number of cytokines, you invariably increase your body’s susceptibility to illness and protect your immune system.

In a randomized controlled trial published by the International Journal of Clinical Pharmacology and Therapeutics, 24 athletes were administered 10 g of Glutamine per day for six weeks, to determine whether Glutamine supplementation alters immune function in athletes during heavy resistance training.

The results found that T-cell ratings (White blood cells that help mediate immune health) were extremely different between the groups, indicating a positive correlation that glutamine supplementation may be able to restore immune function and reduce the immunosuppressive effects of heavy-resistance training in athletes [R]

Most cells in the human body function with a constant turnover or supply of nutrients. Although glucose is the main fuel source metabolized by most cells, cells of the immune system heavily rely upon glutamine similar or even greater than glucose under catabolic (muscle breakdown) conditions such as high intensity or resistance training [R]. This is the reason why, L-Glutamine is referred to as the fuel source for your immune system [R].

In a study conducted by Oxford Universities Biochemistry Department, 200 elite endurance athletes including distance runners and rowers, consumed a post-workout drink either containing 5g of glutamine, or a placebo immediately after and two hours after exercise. The results indicated that seven days following exercise, 81% of the glutamine group showed no infection post workout, as compared to the placebo group, which showed 49% with no infection [R].

RELATED ARTICLE 7 Best Supplements To Boost Your Immune System

L-Glutamine Benefits: Digestive Health 

Recently L-Glutamine has seen a rise in popularity, due to its impressive benefits on digestive health. L-Glutamine assists in rebuilding and repairing the intestinal tract and lining of your gut by maintaining your body’s nitrogen balance. Glutamine decides when and where to place nitrogen atoms to be most efficient and effective in repairing your body. This can be extremely beneficial for those that have gastrointestinal issues such as leaky gut, and inflammatory bowel diseases such as Chron’s, Ulcerative Colitis and IBS since these conditions are characterized by a high prevalence of intestinal hyperpermeability [R].

Glutamine Benefits: IBS

IBS affects anywhere from 25-45 million people in the United States, which is an estimated 10-15% of the entire population. The exact cause of IBS is unknown and symptoms can be extremely unpredictable and sometimes contradictory. Diarrhea can alternate with constipation and cause horrible stomach pain and bloating.

Medications can help with the symptoms of IBS specifically for constipation or diarrhea, yet most medications are designed to relax the colon and often times, provide minimal relief. Because IBS is a syndrome and not a disease, there is no cure for IBS. Therefore, symptoms must be managed through diet, medication, and positive lifestyle choices.

In a double-blind, randomized control trial, published in the leading international gastroenterology journal, Gut 115 patients were administered 15g of L-Glutamine or a placebo for 8 weeks. Increased intestinal permeability was defined as meeting a reduction of greater or equal to 50 points on the IBS Symptom Severity Scale. Secondary endpoints included changes in daily bowel movement frequency, stool form as measured by the Bristol Stool Scale, and intestinal permeability. The results were extremely impressive with nearly 80% of the Glutamine group achieving their primary endpoint. Glutamine also significantly reduced daily bowel movement frequency (3 vs. 5) and Bristol Stool Scale scores (4 vs. 6.5) and normalized intestinal permeability. [R]

RELATED ARTICLE Glutamine As A Potential Treatment Option for Irritable Bowel Syndrome (IBS)

Glutamine Benefits: Chron’s Disease

Studies also show that L-glutamine can be beneficial for Chron’s Disease. Chron’s Disease is a chronic relapsing inflammation of the gastrointestinal tract and is traditionally very difficult to treat. [R] With characteristics such as severe diarrhea, bleeding, bloating, stomach pain, and electrolyte loss coping with Chron’s can be severely challenging, frustrating and a bit embarrassing.

Since L-Glutamine plays a key role in feeding the small mucosa of the gut lining and maintaining gut lining integrity, L-Glutamine supplementation could in fact help restore gut permeability in patients with Chron’s disease. [R]

In a randomized controlled trial conducted at the Department of Gastroenterology and Human Nutrition at the India Institute of Medical Sciences, 14 consecutive patients with abnormal intestinal permeability were randomized into a glutamine group and an active control group and were given either glutamine or whey protein at 0.5g/kg per ideal body weight for two months. The study concluded that intestinal permeability significantly improved within the glutamine group. [R]

According to the Canadian GI Society of Intestinal Research, “In metabolically stressed individuals there is an increased demand for L-Glutamine, making supplementation essential. This includes people with acute or chronic bowel disease, burns, trauma, sepsis, or immune disorders, and can include people with temporary increased metabolic needs resulting from extreme physical activities.

In both healthy and stressed individuals, glutamine is a fuel source for cells in the small intestine and large bowel. It is the preferred fuel source by the gut and is necessary for the maintenance of gut villi, therefore, preventing bacteria from entering the small intestine or bowel wall.

Evidence shows glutamine supplements may benefit Crohn’s disease. Patients with Crohn’s disease have been shown to benefit from oral glutamine, especially in preventing gut permeability associated with taking indomethacin.” [R]

RELATED ARTICLE 14 Studies That Prove L-Glutamine Supports IBD & Digestive Health

Glutamine Benefits: Leaky Gut

Leaky Gut syndrome, is characterized by an increase in intestinal permeability, meaning those harmful ailments and bacterial substances can get through your gut lining, causing inflammation, infection, bloating, and stomach pain 

Since L-Glutamine is the preferred fuel source for the mucosa of the small intestine, your body is able to rebuild and repair your gut lining to mitigate the toxins from crossing your gut lining.

An overwhelming body of evidence suggests that L-glutamine supports and maintains gut barrier function and strengthening gut lining, to reduce intestinal permeability and help treat leaky gut syndrome.

L-Glutamine is to your gut wall, what protein powder is to your muscles. L-Glutamine is in fact the primary fuel source, utilized by the epithelial cells in your gut lining. In simpler words, they love it. 

RELATED ARTICLE L-Glutamine Could Help Heal Your Leaky Gut Syndrome

L-Glutamine Benefits: Increased Muscle Mass

L-Glutamine promotes a positive nitrogen balance, which is also required for the process of muscle protein synthesis. Muscle protein synthesis is known as a muscle-building state, superficially the process of generating amino acids into new proteins. L-Glutamine also reduces muscle mass breakdown or catabolism, helping with muscle tissue repair, leading to an increase in muscle mass.

The specific mechanism of action has not been discovered, yet there has been evidence suggesting that there is a relationship between Glutamine, branched-chain amino acids (BCAAs) and protein metabolism. Since glutamine controls nitrogen balance, and BCAAs are the major nitrogen source of the body, glutamine essentially acts as the trigger for muscle tissue development. It also has an inhibitory effect on the breakdown of body proteins and decreases BCAA catabolism, expressing a direct effect on BCAA metabolism [R,R].

L-Glutamine Benefits: Faster Recovery

Your training isn't over until you recover and recovery is crucial to your overall performance. L-Glutamine is the most abundant conditionally essential amino acid in the human body. However, with increased training volume, glutamine stores are depleted faster than your body can replenish them, which can cause your body to be catabolic and break down lean muscle mass

Exercise-induced muscle soreness is created by micro-tears in the muscle fiber and can cause extreme physical discomfort, tenderness, and even debilitating pain. So bad that you can even develop what's called delayed onset muscle soreness or DOMS. The faster you can recover, the better-quality workouts you’ll have, which translates into improved athletic performance. 

The reason why L-Glutamine is the best supplement for muscle recovery is that L-Glutamine protects against exercise-induced muscle mass breakdown and improves protein metabolism, which helps reduce post-workout muscle soreness. Studies have shown that the anti-catabolism (protection against break down) effects of glutamine have a direct effect on reducing soreness ratings associated with resistance training, due to improving muscle tissue repair. [R]

With less soreness and faster recovery, you can increase training volume. Increased training volume translates to more training and better results.

In another study conducted by the School of Health and Exercise Performance in the division of Kinesiology at Dalhousie University, Halifax, Nova Scotia, Canada.  Sixteen healthy participants volunteered in a double-blind, randomized, placebo-controlled crossover study to examine the effects that L-glutamine supplementation has on muscle strength and soreness ratings following eccentric exercise. The results concluded that supplementation of L-Glutamine directly influenced faster recovery of peak torque and diminished muscle soreness following eccentric exercise [R, R].

RELATED ARTICLE Why L-Glutamine Is The Best Supplement For Faster Muscle Recovery And Soreness

L-Glutamine Benefits: Improves Hydration

An often-overlooked aspect of muscle recovery and reducing muscle soreness is hydration. If you are dehydrated following a workout, the process of protein synthesis will be hindered and subsequently delay the recovery process [R]

In a study published in the Journal of the International Society of Sports Nutrition, ten male subjects were administered 0.3g of L-Glutamine or a placebo to examine the effects of L-Glutamine ingestion on hydration during endurance exercise. The results found that time to exhaustion was significantly reduced and performance levels were significantly improved with higher concentrations of L-Glutamine. L-Glutamine uptake by the skeletal muscles resulted in greater sodium uptake. The enhanced sodium uptake by skeletal muscle may have contributed to a reduction in fatigue by maintaining strength and efficiency of muscle contractility [R]

Therefore, a great benefit of L-Glutamine is in its ability to help sodium uptake for better hydration during training, making it a great supplement for faster muscle recovery.

What Is The Best L-Glutamine Supplement? 

When you’re looking for the best L-Glutamine supplement the first thing is to make sure it’s in powder form, not a capsule. Since the recommended dose is around 20g per day, taking 30 capsules a day could get a bit overwhelming and expensive. Not to mention, it’s easier for your body to digest and utilize right away.

• Unflavored– Look for an L-Glutamine supplement that is unflavored and odorless.
• No Fillers– You want a supplement that is pure 100% micronized L-Glutamine to help ensure proper uptake and use. Make sure you look at the ‘other ingredients’. Most sports supplements contain other amino acids and ingredients you don’t need.
• Higher Dose– Most L-glutamine will have low doses per serving, around 2-3.5 grams. Make sure you get a supplement that has 5g per serving so you get a better value per serving and a higher dose.
• Transparent- Making sure the quality of the supplement you're buying is important, especially since you're trying to avoid additives that could potentially harm your gut health. 

If you're looking for a L-Glutamine supplement to help heal your leaky gut that meets all of these standards, I recommend checking out Swolverine's L-Glutamine. With 100 unflavored micronized pharmaceutical grade servings, at 5g per serving, it's the best supplement to help heal your leaky gut. 

How Much L-Glutamine Should I Take? 

The research indicating the effective dose of L-Glutamine supplementation varies widely from study to study. L-Glutamine is most effective when taken on an empty stomach without food.

In regards to athletic performance, faster recovery and reduced exercise-induced muscle soreness a conventional dose of 5-10g per day is recommended, depending on the severity of soreness.

For those experiencing IBS, The recommended dose of L-Glutamine for IBS is anywhere from 15-20g per day. 

The recommended dose of L-Glutamine for Leaky Gut is anywhere from 20-30g per day.

The recommended dose of L-Glutamine for Chron’s, Ulcerative Colitis, or other IBD is dependent upon disease state, yet the average dose is 30g per day.

When Should I Take L-Glutamine?

For those supplementing with L-Glutamine as an ergogenic aid, L-glutamine should be dosed either before, or after training. An extra 5g dose of L-Glutamine is recommended for heavier lifting training sessions.

Those experiencing gastrointestinal issues and IBD should be supplement Glutamine on an empty stomach, once in the morning with 10-15g and once at night with 10-15g.

The Ultimate Guide To L-Glutamine: Takeaway

Like we said in the beginning, L-Glutamine is underrated. It’s no surprise that this superstar amino acid is gaining popularity. For years, L-glutamine was primarily used as an ergogenic aid, to help with athletic performance, since it helps with exercise-induced muscle soreness, and reduces muscle mass breakdown. L-Glutamine is now being recognized for it’s versatile benefits, especially amongst those in holistic/naturopathic medicine and gastroenterologists, regarding its benefits on gut health and IBD. If anything, L-Glutamine is by far one of the most versatile and impressive amino acids there is.

Thinking About Supplementing With L-Glutamine?

SWOLVERINE is an endurance athlete and active lifestyle brand. Made for the elite athlete, and the strong-willed our products were designed to fuel your athletic performance. We perform when you perform. 

We believe that everyone can optimize not only their athletic performance but their human potential. The way we believe we can optimize performance is through transparency, clinically effective doses, and clinically proven ingredients with evidence-based outcomes. We provide the nutrients you need to power your active lifestyle.

References

Cruzat, Vinicius et al. “Glutamine: Metabolism and Immune Function, Supplementation and Clinical Translation.” Nutrients vol. 10,11 1564. 23 Oct. 2018, doi:10.3390/nu10111564

Legault Z, Bagnall N, Kimmerly DS. The Influence of Oral L-Glutamine Supplementation on Muscle Strength Recovery and Soreness Following Unilateral Knee Extension Eccentric Exercise. Int J Sport Nutr Exerc Metab. 2015;25(5):417-26

Song QH, Xu RM, Zhang QH, et al. Glutamine supplementation and immune function during heavy load training. Int J Clin Pharmacol Ther. 2015;53(5):372-6.

Holecek M. Relation between glutamine, branched-chain amino acids, and protein metabolism. Nutrition. 2002;18(2):130-3.

Cleary, Michelle A et al. “Dehydration and Symptoms of Delayed-Onset Muscle Soreness in Hyperthermic Males.” Journal of Athletic Training 40.4 (2005): 288–297. Print.

Hoffman, J., Ratamess, N., Kang, J., Rashti, S., Kelly, N., Gonzalez, A., Stec, M., Anderson, S., Bailey, B., Yamamoto, L., Hom, L., Kupchak, B., Faigenbaum, A. and Maresh, C. (2018). Examination of the efficacy of acute L-alanyl-L-glutamine ingestion during hydration stress in endurance exercise.

Cruzat VF, Krause M, Newsholme P. Amino acid supplementation and impact on immune function in the context of exercise. J Int Soc Sports Nutr. 2014;11(1):61.

Rodas PC, Rooyackers O, Hebert C, Norberg Å, Wernerman J. Glutamine and glutathione at ICU admission in relation to outcome. Clin Sci. 2012;122(12):591-7.

Daniyah A A, Mahmoud M A. Effect of Glutamine Supplementation in Patients with Inflammatory Bowel Diseases. Nutri Food Sci Int J. 2016; 1(5): 555574. DOI: 10.19080/NFSIJ.2016.01.555574 

Oliveira GP, Diasi CM, PelosiP, Patricia RM (2010) Understanding the mechanisms of glutamine action in critically ill patients. An Acad Bras Cienc 82(2): 417-430.

Kathleen A and Julie J (2004) Inflammatory Bowel Disease Part II: Crohn’s Disease -Pathophysiology and Conventional and Alternative Treatment Options. Alternative Medicine Review 9:4.

Liu, Yulan et al. “Therapeutic Potential of Amino Acids in Inflammatory Bowel Disease” Nutrients vol. 9,9 920. 23 Aug. 2017, doi:10.3390/nu9090920

Den hond E, Hiele M, Peeters M, Ghoos Y, Rutgeerts P. Effect of long-term oral glutamine supplements on small intestinal permeability in patients with Crohn's disease. JPEN J Parenter Enteral Nutr. 1999;23(1):7-11.

Benjamin J, Makharia G, Ahuja V, et al. Glutamine and whey protein improve intestinal permeability and morphology in patients with Crohn's disease: a randomized controlled trial. Dig Dis Sci. 2012;57(4):1000-12.

(n.d.). Retrieved from https://www.badgut.org/information-centre/health-nutrition/glutamine/

Daniel J. Mulder, Angela J. Noble, Christopher J. Justinich, Jacalyn M. Duffin; A tale of two diseases: The history of inflammatory bowel disease, Journal of Crohn's and Colitis, Volume 8, Issue 5, 1 May 2014, Pages 341–348

Zhang Y., Lu T., Han L., Zhao L., Niu Y., Chen H. l-glutamine supplementation alleviates constipation during late gestation of mini sows by modifying the microbiota composition in feces. BioMed Res. Int. 2017;2017 doi: 10.1155/2017/4862861

Rhoads J.M., Wu G. Glutamine, arginine, and leucine signaling in the intestine. Amino Acids. 2009;37:111–122

Kim, Min-Hyun and Hyeyoung Kim. “The Roles of Glutamine in the Intestine and Its Implication in Intestinal Diseases” International journal of molecular sciences vol. 18,5 1051. 12 May. 2017, doi:10.3390/ijms18051051

Lorenzo AG, Zarazaga A, Garcıa Luna PP, Gonzalez Huix F, Lopez Martınez J, et al. (2003) Clinical Evidence for Enteral Nutritional Support with Glutamine: A Systematic Review 19: 805-811

Zhou Q, Verne ML, Fields JZ, et al. Randomised placebo-controlled trial of dietary glutamine supplements for postinfectious irritable bowel syndrome. Gut. 2018;

Rao, RadhaKrishna and Geetha Samak. “Role of Glutamine in Protection of Intestinal Epithelial Tight Junctions” Journal of epithelial biology & pharmacology 5,Suppl 1-M7 (2011): 47-54 

Visser, Jeroen et al. “Tight junctions, intestinal permeability, and autoimmunity: celiac disease and type 1 diabetes paradigms.” Annals of the New York Academy of Sciences vol. 1165 (2009): 195-205. doi:10.1111/j.1749-6632.2009.04037.x 

Castell LM, Poortmans JR, Newsholme EA. Does glutamine have a role in reducing infections in athletes?. Eur J Appl Physiol Occup Physiol. 1996;73(5):488-90.