Glutamine supplements are marketed at bodybuilders, endurance athletes and any of us training at a high intensity. But what do these supplements do, and do we really need them? To answer that question, here’s our trustworthy, robust and scientific NO-BRO ZONE guide reporting the facts, and facts only.
What is Glutamine?
Glutamine is an amino acid, and amino acids are the building blocks of protein, that is, they’re vital in the production of protein and muscle development. Glutamine is the most abundant amino acid in the body and is a ‘non-essential’ amino acid. This means that the body can usually make enough by itself and it isn’t essential that we include it in our diet (unless we’re severely ill or injured).
So that’s it then?
We make enough on our own. What’s the point of a glutamine supplement?
Well, if you’re regularly training at a high intensity, then read on, as it’ll benefit you in ways you might not have thought of.
Most studies on glutamine have shown that it alone doesn’t have an ergogenic effect but that along with protein supplements and other amino acids, it does.
Hold on. Ergo-what?
Ergogenic. In sports, an ergogenic aid is “a technique or substance used for the purpose of enhancing performance”.  They are generally accepted as legal and ethical (i.e. carb loading or taking nutritional supplements such as glutamine), or otherwise (i.e. anabolic steroids).
For the avoidance of doubt, glutamine is accepted as legal and ethical.
What Does Glutamine Do?
Glutamine plays a vital role in the synthesis of protein. So after you’ve worked out, and you’ve caused all those little tears in your muscle fibres, glutamine will, indirectly via protein synthesis, help repair and build them up again.
High levels of glutamine are also thought to increase levels of growth hormone which in turn helps increase muscle mass, which is great for those engaged in weightlifting exercise.
Great. But do we really need to take it in supplement form? You said our body makes enough of it…
Well, you can never have enough of a good thing, so the saying goes. And we did promise you science, so here you go…
The Science Bit (We Read Through the Scientific Studies, So You Don’t Have To)
One, albeit small, Brazilian study , looked at supplementing football players with a carbohydrate drink, vs supplementing others with a mix of carbohydrate and glutamine.
As a quick aside, here’s a note on the difference between glutamine peptides, and L-glutamine. Glutamine peptides are generally found bonded to other amino acids (normally alanine and glycine), whereas L glutamine is ‘free form’. Glutamine peptides are more stable and are much better absorbed and assimilated by the body, whereas L glutamine is ‘purer’.
Back to our Brazilian footballers.
The drink was given to each player (who didn’t know which drink they were getting) half an hour before undergoing a cardiopulmonary exercise test, and their tolerance to exercise was measured using the Borg Scale of Perceived Exertion, a robust method of evaluating fatigue used in many scientific studies.
The study concluded that the mix of protein and glutamine was “more efficient in increasing the distance covered and the length of time for which intermittent exercise was tolerated.” It also “reduced feelings of fatigue” more than that recorded in those with the carb-only drink.
The authors admit that the study was small scale (nine participants) but it’s one in the bag for glutamine, as long as it’s taken alongside a protein supplement.
Further evidence supporting this research is in another study . This study concluded that whey protein with added glutamine and this time also branched chain amino acids (BCAAs) improved both exercise performance and body composition.
We’ve also previously talked about a study that found glutamine supplements had a positive effect on recovery during tests on subjects exercising on an indoor rowing machine. This study also touched on glutamine’s ability to enhance immunity and keep inflammatory responses in check.
Glutamine and Immunity
Ergogenic supplements are generally aimed at enhancing performance, increasing lean muscle mass or reducing body fat. But there’s also evidence that some ergogenic supplements can boost athletic ability by improving the immune system so that an infection is less likely. Glutamine, step forward.
Because as we all well know, illness, no matter how trivial, affects our ability to train.
Free Radicals, Glutamine and Immunity
When we exercise at an intense level, chemically reactive oxygen molecules called ‘reactive oxygen species’ build up. These are otherwise known as free radicals, which you’ve probably heard of. You’ve probably also heard that antioxidants mop up these free radicals.
‘Oxidative stress’ is caused when there’s too many free radicals for the level of antioxidants in the body. Oxidative stress leads to muscle fatigue and injury – so-called Overtraining Syndrome.
We’ve mentioned already that glutamine peptides are more stable and therefore more readily absorbed into the blood than L glutamine. Glutamine peptides are transported to the white blood cells of the immune system, leaving the L glutamine to be used by the glutamine depleted muscles after exercise, acting as an antioxidant hero by speeding up the recovery from oxidative stress .
There’s also evidence that in the recovery period post-oxidative stress, that our immunity weakens, leaving us susceptible to infection.
Decent levels of glutamine in the blood are vital for a well-functioning immune system, whether we’re an athlete or not. After intense exercise, levels of glutamine are reduced. There are many studies therefore demonstrating the need for athletes and sports enthusiasts to take glutamine supplements after exercise.
One  showed that a group given glutamine two hours after an intense training session reported considerably fewer infections in the following weeks than those given a placebo.
So that’s loads more in the bag for glutamine in the case of a strengthened immune system.
Glutamine also encourages cells to take in more water and sodium, and release more potassium. This results in more hydrated cells, a more hydrated athlete able to recover more quickly and with more resistance to injury. It also has a positive effect on the levels of markers of inflammation that are increased by strenuous exercise .
Alriiiight! So, How Much Should I Be Taking, and When?
It depends on the brand, and whether you prefer to take powders or capsules, so it’s a good idea to check the label of the glutamine that you choose to take. But as a general rule, for bodybuilding, aim to take around 15g a day. Split this into three doses, one in the morning, one post exercise and one in the evening. You can take more, up to 40g per day.
Anything Bad About it?
No, there are no known side effects.
But as we’re responsible folk here, we must mention that there are studies that have found for example that “neither short-term nor long-term glutamine supplementation has an ergogenic effect on muscle mass or strength performance” .
So whilst this may or may not be the case (studies continue) we think taking a glutamine supplement that contains both glutamine peptides and L glutamine, along with BCAAs and a whey protein covers all bases – strength, performance, stamina, recovery and have a protective effect on immunity.
Glutamine, you’ve just passed the NO-BRO ZONE exam. Congratulations.