Benefits of Glutamine for athletes and on a daily basis

Benefits of Glutamine for athletes and on a daily basis

Glutamine is one of the 20 amino acids that we get through the diet. It is regarded as a conditionally essential amino acid. This means that it is indispensable under certain circumstances, like intense and prolonged exercise or during a calorie deficit.

What is Glutamine?

Glutamine is the most abundant amino acid in the body, since it makes up around a 60% of all the skeletal muscle tissue. It is by far the amino acid that performs most functions in the organism and it is transformed into glucose when the body needs energy.

It is an indispensable element to build proteins and nucleotides (structural units of Ribonucleic Acid (RNA) and DNA).

There are high concentrations of glutamine in the brain, muscles, intestines, lungs, heart, kidneys, and liver. It is also very important to perform several physiological tasks.

We can find around a 4-8% of glutamine in proteins, like the ones from milk, meat and even walnuts.

Properties of Glutamine

It stimulates the synthesis of proteins and it is indispensable for those athletes who follow an intensive training routine. Some of its benefits are encouraging muscle growth while countering the loss of muscle mass

It also regulates the blood sugar and ensures that the organism has enough glucose to obtain energy. It also regulates the release of the growth hormone, which plays a crucial role in the metabolism of fat and muscle growth.

Glutamine for athletes

The clinical studies have proven that L-glutamine increases the natural release of the growth hormone in a 400%. It also increases the testosterone in a 200% if it is taken after training or doing physical exercise.

It helps to regulate the pH of the body and ensures the acid-base balance. This is indispensable for a proper functioning of the cells. Moreover, it also works as a neurotransmitter so that the cells can communicate between each other.

It encourages a good intestinal tract health and protects it against the onset of damage and stomach ulcers. Moreover, it is involved in the transport of nitrogen in the organism. This process is carried out through the transport of the cells from different chemical reactions. Thanks to this, our body can perform the synthesis of proteins and creatine.

What does Glutamine do in the body?

  • Being a precursor form of the synthesis of proteins
  • Transporting nitrogen between organs and tissues and being involved in the transamination and homeostasis of amino acids. It also gives and takes nitrogen molecules.
  • Supporting active cell replication.
  • Supplying a good source of carbon for the neoglycogenesis and the Krebs cycle in some cells like the enterocytes.
  • Preventing muscle catabolism.
  • Providing very important substrate for the synthesis of glutathione, which is the main endogenous antioxidant (it protects and eliminates toxins from the liver).
  • Serving as the main metabolic fuel.

Glutamine functions

Benefits of Glutamine

Regardless of your objective, either gaining muscle or burning fat, the first step is get to work! Then you have to recover and if you want to succeed, you need to know that both concepts are closely connected.

At this point, the role of glutamine is crucial and some of its benefits are:

  • Increasing the muscle growth rate
  • Reducing the muscle catabolism
  • Enhancing the immune system

This will be extremely important if we want to encourage an anabolic environment that will gather those hormones that are involved in muscle growth.

Benefits for athletes

Glutamine provides a great support for athletes. It regulates the creation of muscle tissue and it is involved in the accumulation of muscle glycogen.

If there is a glutamine deficit, you will be prone to muscle breakdown

It has been reported from several studies that glutamine counteracts the effects of cortisol caused by physical activity.

The glutamine levels can drop due to an injury, trauma, infections, burns, stress and several diseases. These factors can empty the glutamine deposits in the muscles.

Intense training

Other important factors that we should take into account when it comes to sport:

Intense Training

Under these circumstances, the net glutamine consumption exceeds its own production, which reduces the protein synthesis. This contributes to a loss of muscle and tissues, which is frequent in athletes who undergo a high physical wear.

Using glutamine supplementation will help us to improve our recovery, which will result in the following benefits:

  • Stimulation of protein synthesis through the retention of nitrogen
  • Increased growth hormone levels which produces positive changes in the physical composition and the mood as well
  • Reduced muscle catabolism during exercise
  • Increased resistance by recharging the glycogen deposits when they are almost empty
  • Shortened muscle recovery
  • Low risk of suffering infections or diseases by enhancing the immune system
  • Prevent over-training, which can happen due to a high volume and duration of physical exercise

These are some of the properties of glutamine when it comes to improving the athletic performance.

Glutamine to Gain Muscle Mass

Glutamine is frequently used to increase the muscle mass of athletes. However, the studies on healthy beings without deficiencies is not enough to support this claim. Even though it has been proven that a glutamine intake increases the anabolism and prevents the catabolism related to its deficit (MacLennan et al, 1987).

Candow et al, 2001. concluded that oral glutamine supplementation did not produce significant effects on the physical composition of healthy young adults. The study used a dose of 0.9g of glutamine per kg of lean body weight in trained adults vs the same amount of placebo.

It seems to be that this is the determining factor. We will be healthy if we follow a healthy diet and ensure a proper protein supply. If we are already healthy, glutamine supplementation seems to be a bad strategy if we want to increase our muscle mass. However, this does not mean that it is a useless amino acid. In fact, its deficiency is related to unwanted catabolic states, which means that the quantity is not what matter, quality does.

Intravenous Glutamine

However, everything changes when we talk about intravenous glutamine. MacLennan et al. 1987 reported that there was an increase from 0.67 to 5.0 mM of glutamine in a study with rats. At the same time, this increased the protein synthesis without insulin (exogenous), which would have increased even more with a supply of insulin. Nevertheless, we have to be aware of the fact that the intravenous administration of glutamine is not available for most of the population. Now, you may ask, is glutamine oral supplementation useless? Not at all.

Effects of Glutamine on the muscles

First of all, let’s not forget what we mentioned previously, taking glutamine orally will increase our muscle mass if there is a deficiency of this amino acid. This is due to the fact that we enhance the anabolism and prevent the catabolism. The oral administration of this amino acid has been tested on animals, producing different effects on their physical composition. The intake of food also played a role in this process.

Glutamine for the muscles

However, glutamine has quite interesting therapeutic properties that can benefit both sick and healthy people

Glutamine as Muscle Recuperator
This amino acid can be transformed into glucose when the body needs energy. Glutamine can also stimulate the retention of nitrogen (a positive nitrogen balance) and prevent the loss of muscle protein

Glutamine to Prevent Over-training

It is a syndrome caused by an excessive volume of exercise and especially due to its intensity. This results in unbalanced recovery periods, in which the body does not have time to assimilate all the work. Moreover, it will not be able to “heal” all the internal trauma that is caused by said activity. In addition, the resulting muscle breakdown can even affect the immune system. This makes matters even worse, since it will affect the health of the athlete.

Low glutamine levels will lead to an over-training syndrome if we do not stop or reduce the intensity of our workouts. Bad recoveries, loss of strength and muscle mass, weakness in general…

Benefits of Glutamine for the general population

From what we have explained, we may deduce that glutamine supplementation is only aimed at those who do physical exercise. However, this is false since it is not reserved to athletes and bodybuilders, anyone can benefit from it.

We could say that glutamine plays the same role as vitamins, so we can gather them in the same group!

Surprisingly, this substance can benefit practically anyone, regardless of their lifestyle. Sometimes, glutamine tends to have the lowest value when we check the results of a blood test. This is common especially among patients who are following medical treatment or who have damaged cognitive functions.

If we put aside its benefits for athletes and bodybuilders, these are some of its properties:

Improved cognitive functions

There are important concentrations of glutamine in the brain, between 10-15 times more than in the blood. It works as a modulator of the inhibitory effects of GABA and glutamate stimulants. It is an important fuel for the brain, since it provides energy when there is no glucose available.

This is the reason why it supports the concentration, memory, intellect, vigil, attention, mood and reduces memory loss.

Glutamine supports the heart

It has been recently discovered that glutamine is an important energy source for the heart. This amino acid can be transformed into glutamate, which is involved in the Krebs cycle to produce ATP.

Myocardium patients are given glutamate during the treatment to improve their recovery

Moreover, glutamine serves as substrate for the synthesis of a special type of beta-endorphin called glycyl-l-glutamine. It is a very important dipeptide when it comes to regulating the blood pressure and to prevent a cardio-respiratory insufficiency.

It regulates blood glucose

This process is carried out through several mechanisms. When the sugar levels are low, glutamine inhibits insulin to prevent said levels from dropping even further. At the same time, it stimulates the glycogen reserves to take the glycemia to a more stable level. Furthermore, glutamine is a glycolytic amino acid. This means that it can be transformed into glucose to produce energy through a process called gluconeogenesis.

Increasing the intake of glutamine (diet and supplementation) will help us preserve our muscle tissue and avoid its breakdown into glucose

This is especially relevant for those who follow strict diets in terms of calories and who also want to preserve as much muscle mass as possible.

It preserves the health and proper functioning of the intestine

Athletes undergo a lot of stress on their digestive system and especially the intestine due to the frequency and quantities of food.

In this case, glutamine will be an excellent ally. In fact, many professionals advise using glutamine. This is because they think that most health problems are somehow related to the intestine.

It calms the craving for sweets and alcohol

This is related to the regulation of blood sugar. Several studies with alcoholic people reported that 2-3gr of glutamine 3 times a day reduces the need to drink. At the same it, this lowers the anxiety levels and improves the quality of sleep.

If you crave sweets, take between 5-10gr of glutamine and the feeling will go away…

On the other hand, many people experience a hangover after drinking alcohol. The effects will depend on how much we have drunk. Some of the symptoms are light sensitivity, nausea, dehydration and general discomfort.

When we drink alcohol, it inhibits the synthesis of l-glutamine. This means that the body produces more glutamine than it needs, resulting in a process called glutamine rebound.

This excess significantly increases the brain’s activity while we sleep. Consequently, the body does not get restful sleep. In the morning, the lack of rest and the excess of acetaldehyde results in what we know as hangover.

Alcohol abstinence

Those who become addicted to alcohol have a bad time when they want to quit. Alcohol abstinence can trigger serious symptoms that can last for several days: headaches, tremors, nausea, anxiety, hallucinations and insomnia.

No alcohol

According to the University of California in San Diego, some alcoholics can have a neurotransmitter deficiency. These are chemical substances from the brain that are made up of amino acids such as L-glutamine

Glutamine, when combined with other amino acids, can help to relieve the symptoms of alcohol abstinence. For example, you could take a glutamine supplement along with a multivitamin complex.


L-glutamine can a great support for those who drink alcohol. However it is not a cure for alcoholism or a remedy to avoid drinking too much.

If you want to take glutamine, consult your doctor in case you are taking any kind of medicine or drinking alcohol.

It improves the wound healing process

The cells that forms the connective tissue of the organism are called fibroblasts, and they use glutamine to synthesize proteins and around a 30% to meet the energy requirements. The amino acid glutamine is necessary for their proliferation which is why it is essential for wound healing.

This will be extremely beneficial for athletes in terms of preserving the health of the connective tissue of the joints, specially after a workout session

Glutamine and Health

Digestive System

Glutamine is an amino acid that has been widely use to treat gastrointestinal disorders. Many athletes undergo bulking and cutting phases which involve eating huge amounts of food, resulting in very difficult digestions. Then, they have to cut the energy intake and they use hyper-palatable products with sweeteners, many poly-alcohols… all of this in order to cope with the anxiety that is caused by the caloric restriction.

Glutamine improves the intestinal health

We know that those diets that are low in FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) are being increasingly used in patients with leaky gut syndrome and other gastrointestinal disorders. (Halmos et al, 2016)

This is due to the fact that consuming these compounds alters the intestinal microbiota, which increases the negative symptoms. Glutamine plays a very interesting role in the intestinal health since: “a lack of glutamine can result in the deterioration of the intestinal walls” (Van der Hulst et al, 1996).

Effects on the digestion

Glutamine performs several tasks that affect the digestion. It protects the mucosa from the intestines and stomach. In fact, low glutamine levels can affect the digestion. Some studies suggest that people with gastrointestinal problems do not have enough glutamine in the intestines. Consequently, this can lead to a loss of weight and muscle mass.

Amino acid glutamine

Glutamine supplements tend to be prescribed to treat these disorders. However, clinical research has not reported concluding results about the effects of glutamine on gastrointestinal diseases and the digestion. We still need more research.

Intestinal Flora

Those who suffer intestinal discomfort can benefit from the positive effects of glutamine supplementation such as: protection for the gastrointestinal mucosa, control over leaky gut and a better functionality and morphology of the intestines. Rao et al, 2012.

Intestinal problems among athletes

This would result in the relief of the intestinal discomfort in periods of irregular eating patterns which are so common among athletes. It would also improve the symptoms of people with gastrointestinal pathologies, by improving the absorption and absorption of nutrients. In addition, it would also improve the intestinal flora and microbiota.

Glutamine and the Immune System

This amino acid is indispensable for our immune system. This is due to the fact that “it is used by the immune system cells to preserve the lymphocyte proliferation and the production of cytokines by the lymphocytes and macrophages” (Calder et al. 1999)

Glutamine enhances the immune system

Oral glutamine supplementation can reduce the damage to the muscles and the inflammation caused by demanding workouts. (Cruzat et al, 2014).

Glutamine and Glutathione

Another property of glutamine is that it is a precursor form of glutathione, which is one of the most important antioxidants. We increase the production of ROS when we do physical exercise or when we experience stressful circumstances (surgery, injuries, trauma, catabolic states, infra-nutrition). This produces damage to the cells, apoptosis and even necrosis, since the cell may not be able to recover…

Glutamine for cell health

This is the reason why glutamine supplementation is important to trigger a redox reaction that will preserve the health of the cells.

Glutamine and Glutamic Acid

These are different substances, but they are closely related. They are non essential amino acids, that is, the body can synthesize them on its own. Moreover, they also have similar structures and perform important roles in the organism.

Conversion of Glutamic Acid to Glutamine

Glutamic acid and Glutamine are interchangeable, which means that they can become one another according to our requirements. Both have a similar molecule chain; glutamine has an amide group while glutamic acid has a hydroxyl group bound to its chain.

Effects on the Organism

Glutamic acid can make up several proteins or it can act as a free amino acid. The latter will be actively involved in the urea cycle which transforms ammonia in urea. First of all, glutamic acid reacts to the ammonia, which results in the production of glutamine. Apart from preventing the toxicity due to an ammonia accumulation in the body, it can cross the blood/brain barrier. It will be easily transformed into glutamic acid back again once it reaches this organ.

Brain Function

Glutamic acid works as a brain neurotransmitter. The synopsis is a process through which neurons share information. The brain structures where this process takes place use glutamic acid as a transmitter, which stimulates the brain function. Moreover, it binds to nitrogen atoms in the brain and detoxifies the ammonia from the brain.

It is advisable to take glutamine in the following cases:

  • To accelerate the growth of muscle when we do physical exercise
  • If you are an immuno-compromised patient
  • When there is risk of suffering infections
  • After a serious surgery
  • To relieve mental and physical stress

What are the sources of Glutamine?

Some of the best sources of this amino acid are meat, fish, wheat and dairy products. Quark or cottage cheese have a particularly high content of this amino acid.

It is heat-resistant, which is why cooking these foods will not alter the glutamine content. It is also available as a dietary supplement of L-Glutamine or Glutamic Acid.

What are the symptoms of a glutamine deficiency?

It is an essential element for our body, which is why a deficiency can cause important damage to our immune system. Even a small amount will make a difference when it comes to being more susceptible to infections.

This is due to the fact that it is in charge of protecting the mucous membranes. The body is more exposed to viruses and bacteria when it does not have enough glutamine.

The physical and mental performance can be considerably affected by a deficiency as well. This will result in a low muscle tone, the inability to perform efforts and a lack of concentration. Moreover, the body will also need more glutamine after a surgery.

Daily Dose of Glutamine

Before giving any number, we should be aware that this amount will change depending on individual circumstances like the type of activity, its intensity, recovery patterns, diet, supplementation…

Usually, we get around 3-6gr daily through the diet, by maintaining a protein supply of 1.5g per kg of body weight approximately.

Recent research shows that the effects of high intensity exercise on the glutamine levels in plasma require 0.1gr of glutamine per kg of weight every 30 minutes after training for a period of 2-3 hours.

The commonly recommended dose moves between 2-20gr divided at certain times like the post-workout and before going to sleep. Other suggested serving could be after waking up and just before training, which are less relevant in this case

It is not necessary to cycle the glutamine, moreover, it is advisable to make sure that its deposits are in optimal conditions while we practice the sport activity.

Are you interested in purchasing glutamine supplements to improve your sport performance? Click here!

Side effects of glutamine

Glutamine supplements are safe. There are a few side effects that are usually triggered by a high dose what would range between 2 and 20 grams daily.

In case of overcoming them, you may experience allergic reactions like:

  • Urticaria
  • Tight chest
  • Swelled face, hands or mouth
  • Difficulty to breathe

Possible contraindications of glutamine

Glutamine should be avoided by:

  • People who suffer hepatic diseases
  • The elderly, unless it is prescribed by a doctor with an specific dose
  • Children under the age of 10
  • Those who suffer epilepsy or bipolar disorder
  • Pregnant and lactating women, since there are not enough studies

What do the Experts think?

GLutamine is one of the most controversial ingredients within sport supplementation. Many athletes are not aware of its existence or they do not give it the attention it deserves, which results in a completely underestimated opinion about its effects in supplementation. However, experience tells us this is not true, since there are plenty of cases that have proven that its continuous use provide excellent results.

From my point of view, if you do physical exercise, you have a sport and nutritional strategy, and you pay attention to all the variables, I think that glutamine can be a great help to all those who want to achieve a esthetic body, while improving the performance through the correct recovery processes.

Glutamine supports the recovery


  • Reestablishing the myosin chains which determine the contractile activity of the muscle
  • Saving and producing glycogen
  • Protecting the immune system
  • Stimulating the protein synthesis
  • Producing anti-catabolic effects
  • Increasing the growth hormone values

The Importance of Glutamine

Glutamine is especially important for:

  • Athletes who do strength and power sport, as well as intense physical exercise
  • Improving the physical performance in general
  • Patients with a weak immune system
  • Those who suffer from an intestinal disease
  • People who undergo a lot of stress
  • Increasing the concentration
  • Shortening the recover after a surgery
  • Unstable sugar levels
  • Supporting weight loss diets
  • Stimulating the intellectual performance


  • Miller, A. L. 1999. Therapeutic considerations of l-glutamine: a review of the literature. Alternative Medicine Review 4:239-248; Antonio, J, et al. 1999. Glutamine: a potentially useful supplement for athletes. Canadian Journal of Applied Physiology 24: 1-14.
  • Griffiths M, Keast D. The effect of glutamine on murine splenic leucocyte responses to T- and B- cell mitogens. Cell Biology 1990;68:405-408.
  • Newsholme EA. Psychoimmunology and cellular nutrition: an alternative hypothesis. Biol Psychiat 1990;27:1-3.
  • van Hall G, Saris WH, van de Schoor PA, et al., The effect of free glutamine and peptide ingestion on the rate of muscle glycogen resynthesis in man. Int J Sports Med 2000 Jan;21(1):25-30.
  • Bowtell JL, Gelly K, Jackman ML, et al., Effect of oral glutamine on whole body carbohydrate storage during recovery from exhaustive exercise. J Appl Physiol 1999 Jun;86(6):1770-7.
  • Calder, PC & Yagoob, P. (1999). Glutamine and the immune system. Amino Acids. 17(3), 227-41.
  • Candow, DG; Chilibeck, PD; Burke, DG; Davison, KS & Smith-Palmer, T. (2001) Effect of glutamine supplementation combined with resistance training in young adults. Eur J Appl Physiol, 86(2):142-9. 10.1007/s00421-001-0523-y.
  • Cruzat, V. F., Krause, M., & Newsholme, P. (2014). Amino acid supplementation and impact on immune function in the context of exercise. Journal of the International Society of Sports Nutrition, 11, 61.
  • Halmos, E. P., Christophersen, C. T., Bird, A. R., Shepherd, S. J., Muir, J. G., & Gibson, P. R. (2016). Consistent Prebiotic Effect on Gut Microbiota With Altered FODMAP Intake in Patients with Crohn’s Disease: A Randomised, Controlled Cross-Over Trial of Well-Defined Diets. Clinical and Translational Gastroenterology, 7(4), e164–.
  • MacLennan, PA; Brown, RA & Rennie, MJ. (1987). A positive relationship between protein synthetic rate and intracellular glutamine concentration in perfused rat skeletal muscle. Febs Lett., 4;215, 187-91.

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About Alfredo Valdés
Alfredo Valdés
He is a specialist in metabolic physiopathology training and in the biomolecular effects of food and physical exercise.
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  1. I was really concerned about the benefits and some special benefits of glutamine. This really helped alot.

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