Are you taking advantage of the benefits of l-glutamine? Check out the top 5 benefits of l-glutamine and why this supplement should be in your post-workout shake!

Glutamine could be one of, if not the most underrated and undervalued supplements when it comes to improving your health, wellness, and athletic performance. Compared to other sports nutrition products, glutamine may not directly influence athletic performance outcomes such as speed, strength, and rep volume.  What it does do, however, is keep your body working like a well-oiled machine. Studies prove that l-glutamine benefits your immune system health, digestive health, and accelerates the recovery process. In fact, glutamine could be the best supplement for post-workout muscle recovery ever created.

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What Is L-Glutamine?

L-glutamine is what’s known as a conditionally essential amino acid. Conditional meaning that in certain conditions, it becomes essential to supplement or obtain from dietary sources. Your body naturally produces glutamine, yet in times of severe physical stress or trauma, such as prolonged workout durations, and high-intensity training, glutamine stores may become depleted, making it necessary to replenish and restore through supplementation.

Of the twenty amino acids, l-glutamine is objectively the most abundant and naturally occurring amino acid in the human body, constructing nearly 60% of the amino acid pool in your muscle tissue. Like other essential amino acids, yet unlike non-essential amino acids naturally produced by the body, l-glutamine can cross the blood-brain barrier, giving it the ability to freely enter the brain, making it vital in the process of nitrogen transport, acid-base regulation, gluconeogenesis, while also working as a precursor of nucleotide bases and the antioxidant glutathione.

Related: A Brief & Thorough Guide to Amino Acid Supplementation

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5 Benefits of L-Glutamine

1. Accelerates Recovery Times & Reduces Soreness

Exercise soreness is a natural by-product of your training, and a fundamental part of the muscle building and rebuilding process. However, too much muscle soreness can impede your training performance and cause more harm than good. Optimizing your post-workout muscle recovery is crucial to continue training and making gains. 

L-Glutamine plays a vital role in helping your muscles rebuild and repair themselves, to prevent muscle soreness and aid in faster muscle recovery.  L-Glutamine inhibits muscle mass breakdown and improves protein metabolism, thus improving exercise-induced 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, theoretically putting your body back into an anabolic state.

In a randomized, double-blind controlled study conducted by the School of Health and Human Performance, at Dalhousie University, 16 healthy participants were either administered a placebo or 0.3 grams of l-glutamine per kg of body weight every day for a 72-hour period after an eccentric exercise involving knee extensions. The study concluded that l-glutamine supplementation resulted in faster recovery of peak torque and diminished muscle soreness with lower soreness rating post-workout after a three-day period.1

Remember when I said that in certain conditions glutamine can become essential? Well, during high intensity or prolonged training periods, your body will utilize and deplete your glutamine stores, which will inhibit its function, decreasing strength, stamina, and extending the recovery process. Supplementing with glutamine post workout will ensure that you properly restore glutamine levels to help better rebuild and repair muscle tissue and improve your recovery times.

Studies have shown that glutamine works best when combined with branched chain amino acids, to help restore and replenish amino acid balance, to improve recovery and rebuild muscle mass.

2. Restores Immune System Health

Often overlooked, endurance athletes and bodybuilders training under heavy loads and volume will be more susceptible to infection and illness, suggesting that training may suppress immune system function. Studies have shown that glutamine may benefit immune system function by producing 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.

A randomized controlled trial published by the International Journal of Clinical Pharmacology and Therapeutics, examined the effects of glutamine supplementation and immune system function during heavy weight resistance training. 24 athletes were administered 10g of glutamine per day for six weeks while and assigned either to a control or experimental group. Immune system function was assessed using specific immunity markers as well as T-cell counts.

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.2

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3. Improves Digestive Health

One of the most fascinating benefits of glutamine, is its ability to rebuild and repair your gut lining by maintaining your body’s nitrogen balance. Glutamine decides when and where to disperse and utilize nitrogen atoms to be most efficient and effective in repairing your body. This is not only beneficial for muscle recovery, but 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.3

In a double-blind, randomized control trial, published in the leading international gastroenterology journal, 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.4

Metabolically stressed individuals such as those with inflammatory bowel disease have an increased demand for glutamine, making supplementation critical in maintaining intestinal homeostasis.

According to the GI Society Of Intestinal Research 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 that patients with IBD may benefit greatly from supplementing with glutamine.

Related: 6 Ways Better Gut Health Can Lead to Better Gains

4. Improves Strength Gains

While glutamine is not directly linked to strength parameters, glutamine does promote a positive nitrogen balance which is a required process to facilitates muscle protein synthesis. L-Glutamine reduces muscle mass breakdown also known as muscle catabolism, helping with repairing muscle mass, which will inevitably lead to an increase in muscle mass.

Studies have shown that BCAAs combined with l-glutamine may optimize muscle protein synthesis and reduce muscle mass breakdown, thus improving strength gains and increasing lean muscle mass.

Evidence suggests that there is a direct correlation between glutamine and branched-chain amino acids and the process of protein metabolism. BCAAs are a major nitrogen source, and since glutamine controls nitrogen balance, glutamine acts as a catalyst for muscle tissue development.5

5. Improves Hydration

One of the most surprising benefits of glutamine, is its role in hydration. Hydration is a critical element to optimize the recovery process. Studies have shown that dehydration can increase perceived pain associated with delayed onset muscle soreness, and exacerbate muscle soreness post-workout.6

Recent research demonstrates that glutamine promotes rehydration by enhancing electrolyte and water absorption, due to its ability in rebuilding intestinal lining, reducing hyperpermeability.

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.7

Muscular woman in orange Swolverine sports bra holding a container of Swolverine's L-Glutamine

What’s The Correct Dose Of L-Glutamine?

Research suggests that the clinically effective dose of glutamine is between 5-10g, dependent upon soreness for optimal recovery and performance. For those experiencing inflammatory bowel disease states, 20-30g per day is recommended. In the case of IBD, we suggest that you consult your physician to discuss glutamine as part of your treatment protocol.

Benefits Of L-Glutamine: Takeaway

While glutamine may not have magnetism and lack the pre-workout hype like beta-alanine and creatine, studies have proven that glutamine is extremely versatile and offers several benefits, that can improve and maximize overall athletic performance. Glutamine can decrease your susceptibility to illness, by improving immune system health, optimize your digestive health by rebuilding your gut lining and accelerate recovery times, through the inhibition of muscle mass breakdown and improving post-workout muscle soreness. Overall, adding a scoop of glutamine to your post-workout shake can dramatically improve your muscle recovery and overall health.

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  1. 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 Oct;25(5):417-26. doi: 10.1123/ijsnem.2014-0209. Epub 2015 Mar 26. PMID: 25811544.
  2. Song QH, Xu RM, Zhang QH, Shen GQ, Ma M, Zhao XP, Guo YH, Wang Y. Glutamine supplementation and immune function during heavy load training. Int J Clin Pharmacol Ther. 2015 May;53(5):372-6. doi: 10.5414/CP202227. PMID: 25740264.
  3. 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
  4. Zhou Q, Verne ML, Fields JZ, Lefante JJ, Basra S, Salameh H, Verne GN. Randomised placebo-controlled trial of dietary glutamine supplements for postinfectious irritable bowel syndrome. Gut. 2019 Jun;68(6):996-1002. doi: 10.1136/gutjnl-2017-315136. Epub 2018 Aug 14. PMID: 30108163.
  5. Holecek M. Relation between glutamine, branched-chain amino acids, and protein metabolism. Nutrition. 2002 Feb;18(2):130-3. doi: 10.1016/s0899-9007(01)00767-5. PMID: 11844643.
  6. Cleary, Michelle A et al. “Dehydration and symptoms of delayed-onset muscle soreness in hyperthermic males.” Journal of athletic training vol. 40,4 (2005): 288-97.
  7. Hoffman, J.R., Ratamess, N.A., Kang, J. et al. Examination of the efficacy of acute L-alanyl-L-glutamine ingestion during hydration stress in endurance exercise. J Int Soc Sports Nutr 7, 8 (2010).