The Benefits of L-Glutamine Supplementation

There are some supplements that don’t get as much love as they should, like L-glutamine. A post-workout supplement most don’t take but should consider doing so, here’s why...

The Benefits of L-Glutamine Supplementation
7 min. read 2/10/2022, 3:58 PM

Amino acids are found all over your body, working around the clock to build all kinds of proteins to help you stay healthy and in good shape. There are 20 of these amino acids, and they’re all important for different reasons, but today we’re talking about a hidden champ: glutamine. A well-known name in the fitness world, athletes and lifters are familiar with L-glutamine as a post-workout supplement thanks to its muscle recovery benefits. But, is it as effective as it sounds? And how exactly does it work in your body? We’ll tell you all about it, so you can decide whether it’ll be a part of your supplement pantry, or not.

What is glutamine?

Glutamine is the most abundant amino acid in your body, making up to 60% of the total amount of amino acids found in your cells. It exists in two forms: L-glutamine and D-glutamine, and while the latter isn’t particularly relevant to living organisms, L-glutamine definitely is. Amino acids are the building blocks of protein, so L-glutamine plays a significant role in your organism, helping with the transport of carbon and nitrogen through your body and supporting your immune system and intestinal health. While glutamine is not a part of the nine essential amino acids because your body (and specifically your muscle tissue) can produce it on its own, it is still considered a “conditionally essential” amino acid. This is because sometimes the amount of glutamine that you need is greater than what your body is able to produce, such as when you’re sick, injured, or working out at a high intensity since your body is under a lot of physical stress. When this happens, you need to turn to high-protein food sources (such as eggs and meat) and supplements to make up for that deficiency, which is why glutamine is commonly taken as a post-workout supplement in order to support your muscle health and recovery after exercise.


L-glutamine presence in the body is essential in order for it to function optimally, and when your body’s reserves are depleted, supplementation can be extremely helpful. Some of its most significant health benefits are:

  • Helps maintain gut health

Glutamine acts as an energy source for your intestinal cells, helping with their growth and maintenance, and it’s also used as fuel to repair intestinal damage when needed. This is the reason why you may have a glutamine deficiency if you’re ill or injured since your body is tapping into your glutamine storages to fix the issues. It also serves as an important barrier between your intestine and the rest of your body, basically filling the gaps and protecting the body from a leaky gut by giving your intestines impermeability and preventing harmful bacteria, toxins, and even undigested food from entering your bloodstream.

  • Supports the immune system

Due to the high amount of intestinal cells with immune functions, L-glutamine also helps support the immune system by maintaining your gut health in tip-top shape. It acts as an important fuel source for immune cells and promotes immune cell production, which is relevant to those who work out at high intensities or take part in athletic activities since their immune system tends to get weakened from the constant physical stress that they go through when training. Glutamine supplementation has been proven to have a positive effect in critically ill patients, as well as in patients undergoing abdominal surgery, so it’s known to be beneficial to our immune system when supplemented due to its protective effects. [1]

  • Improves muscle recovery

Avid gym-goers and athletes can benefit from L-glutamine supplementation thanks to its ability to increase muscle recovery time while also reducing muscle soreness. One particular study conducted by the International Journal of Sports Nutrition and Exercise Metabolism found that glutamine supplementation in healthy patients taking part in eccentric exercise saw a faster recovery after an intense leg workout, as well as reduced muscle soreness. The additional glutamine present in the body after supplementation helps promote protein synthesis, speeding up the recovery process altogether, while attenuating the inflammatory response after intense exercise. [2]

  • Helps promote aerobic performance

When the body is under too much stress, it will start tapping into your stored glutamine and turn it into glucose by the liver, acting as an energy source just like carbs and fat, and helping you train for longer. It may also decrease fatigue during exercise, helping with endurance during prolonged aerobic activities. Blood ammonia concentration has been linked to both peripheral and central fatigue, and it typically increases during endurance exercise, but research has shown that after L-glutamine supplementation the accumulation of blood ammonia significantly decreased for the second hour of continuous exercise in high-level athletes. [3]

Additionally, since proteins and amino acids like glutamine slow down digestion and promote the feeling of satiety, glutamine supplementation has also been linked to weight loss along with high-protein diets. This is because they send signals to your brain indicating that you’re full, which helps you reduce your food portions and wait longer between meals, supporting your weight loss goals.

Should you take a glutamine supplement?

Well, that really depends on your diet and activity level! The human body is usually able to produce enough glutamine to meet your needs, and you also get it through high-protein foods, so supplementation is only really suggested if you’re constantly putting your body and muscles under a lot of stress or if you’re injured and/or ill with a glutamine deficiency. If you’re a highly active person, glutamine supplementation could be right for you in order to improve your recovery time after training and reduce muscle soreness. If you have a poor diet, or you’re not consuming as much protein as you should be, glutamine supplementation could also be useful in order to promote gut health and prevent any possible illnesses. Like with any other supplement, you should seek medical advice from your doctor or dietitian first to see if you actually need it and how much should you take, especially if you already have health issues related to your gut or immune system.

As to the potential side effects, as long as you stay within the recommended daily dosage, there shouldn’t be any. L-glutamine is different from other dietary supplements because it’s naturally produced by the body and it’s found in many foods, after all, so supplementing with it is perfectly safe! The recommended daily amount of supplemented glutamine is usually 5 grams in order to meet the body’s needs, but the dosage could vary depending on your activity level. If you’re taking part in athletic activities or high-intensity training, the range could go from 10 to 20 grams per day to make up for the naturally produced glutamine that’s been used up. There have been reported cases of high glutamine dosages causing dizziness, but it stopped once the dosage was reduced.

The most common supplement form available is glutamine powder, so if you decide to supplement with it then there are many ways that you can sneak it into your diet. You can make smoothies with it, blend it with your oatmeal, or even just stir it into a glass of water at any time of the day! It’s also commonly found in some protein powders, so if you’re already supplementing with it, take a look at the ingredients list to see if it has an optimal dose of glutamine. Whichever way you choose to take it, restoring your body’s glutamine levels may help you improve your workouts as well as your overall wellness, so don’t be afraid to give it a try if you feel like it fits your needs!