L-glutamine 2018-02-22T12:45:30+00:00

What is L-glutamine?

L-glutamine is one of the non-essential amino acids in humans. Although the body can produce it, immune system weaknesses and nerve problems can occur during times of high demand.

Couple assist in weighting each other

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Our body uses L-glutamine to create proteins, so-called amino sugars, and to support the production of the super-antioxidant glutathione.

The body also uses L-glutamine to

  • increase water retention in muscle cells,
  • help signalling cell growth and to
  • start intensifying production of protein and glycogen.

Glutamine is therefore a very popular supplement with strength athletes. 

Among the free amino acids in human blood, L-glutamine is the most abundant at around 20% of the total. It also exists in a peptide-bonded state, which makes it chemically very stable.

When do we need L-glutamine

A significant lack of L-glutamine can be detected particularly during times of metabolic ill-health. Examples are post-surgery recovery periods or when suffering from injuries or burns. This often means that appropriate supplementation becomes necessary.

amino acids support the immune system

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Even existing conditions can lead the body to rapidly demand more Glutamine. This demand is most efficiently met with extra L-glutamine using nutritional supplements.

Above all, this versatile amino acid plays a role in the synthesis of amino sugars and other protein chains in the body. This means that it is especially needed by tissues with a high cell division rate.

Examples of these tissues include

  • the immune system,
  • the mucous cells in your small intestine,
  • cells for mucous production in the mouth, such as those on the tongue,
  • cells of the musculoskeletal system, especially in athletes.

A low supply of L-glutamine in your body can therefore lead to a weakening of all of these systems at the same timer. An immune system weaknesses and problems in your digestive system due to infections, and it can affect your quality of life significantly. This can be exacerbated if you exercise a lot.

L-glutamine enables the production of the natural anti-oxidant glutathione, a known preventer of cell damage. It also works as a protection for all cells against oxidising free-radicals and can thus act against the development of cancer too.

As if that were not enough, this amino acid regulates the stability of acids and bases in the body. This keeps the various proteins effective in fulfilling their various roles in the body. This in turn ensures the correct execution of metabolic processes.

Foods high in L-glutamine

The recommended minimum dose of L-glutamine is around 10g per day. This can also be higher if certain specific factors are at play. In most need are competitive athletes and patients with liver or kidney diseases, who frequently need higher doses of up to 40g a day. In those cases nutritional supplements must normally be called upon. Natural foodstuffs tend to contain relatively low levels of L-glutamine. The need for L-glutamine can also rise sharply during chemotherapy, when supplements can often be helpful again.


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As L-glutamine is denaturalized by heat. This means that its chemical structure gets damaged and thus its properties are diminished. Keeping products, which contain L-glutamine in direct sunlight over long periods will therefore result in a continual reduction of the vital amino acid. Storage in dark places is recommended.

Aside from cheese, the German cottage-cheese like product quark is known as the food containing the most L-glutamine. You should thus factor it into your meal plans to provide you with extra amounts of natural Glutamine. Milk and yogurt in general are good providers of L-glutamine, although they contain markedly less in comparison. Raw and smoked meat contain some L-glutamine, as do soya and wheat products, which can all be used to achieve your recommended daily dose.

Doses of L-glutamine

There are different recommendations as to when in the day L-glutamine can best be absorbed into the body. The theory that has stayed its ground the longest is one of consumption both in the morning and the evening. To best strengthen your immune system, taking one dose of 5g of L-glutamine after getting up and another 5g before going to bed is recommended.  If your aim is to build up muscle mass with higher glycogen storage in your muscle tissue, you should take around 5 to 10 grams of Glutamine before and after working out.

glutamine boosts the immune system and transmission of nervous signals

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If your L-glutamine levels drop to lower than your body needs, the consequences can be threatening. Not consuming enough L-glutamine over long periods of time can lead to your immune system having lower levels of activity and problems with absorbing vitamins.

Thus, not only do you then have a higher risk of infections, but also a lack of many other important nutrients because your intestine has not managed to absorb all the nutrients from food you have consumed, leaving them unused.

Benefits of L-glutamine

L-glutamine is used in creating proteins and is therefore involved in the composition of many protein products. Amongst other functions, it helps to create so-called amino sugars, which assist the body in combating things like osteoarthritis, and supports production of glutathione.

Glutamine has been shown to have positive effects on Human Growth Hormone maintenance, immune system function, cell volume, and protein substrate recycling for increased proteine synthesis. These advantages make Glutamine a sensible anabolic supplement which is beneficial & popular with bodybuilders. Supplementation of 5-10g a day is beneficial to restore lost Glutamine in muscle cells1.

As well as this, it puts pressure on fluid retention in cells so that the cell volume can ultimately increase.

The body takes this increase in cell water retention as a signal for cell growth and starts to intensify production of protein and glycogen with the aim of increased performance of muscle cells.

At the same time, L-glutamine prevents muscle catabolism and improves your body’s ability to recover during sleep.

If, however, you are suffering from infection or trauma, the amount of free L-glutamine in your body’s muscle systems will reduce by up to 50%, and symptoms like tiredness and fatigue will occur.

L-Glutamine is multifunctional

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L-glutamine’s role in the digestive system

Because L-glutamine provides energy to the digestive cells, it aids those cells in their regeneration and renewal, therefore influencing the absorption ability of the intestine. Cells which divide quickly, such as those in the immune system too, are very reliant on having a supply of L-glutamine. This is why medical procedures like bone marrow transplants have much lower death rates when a targeted supplementary regime of L-glutamine has been given beforehand.

Other uses of L-glutamine can be found in the nervous system. L-glutamine is very chemically similar to the neurotransmitter glutamic acid. To transport messages in the body, the nerve cells must be stimulated successfully sequentially in a row.

After the initial stimulation, the neurotransmitter has to be transported back to the earlier cell which previously released it in order to pass along the message.  When back in the old cell, it is turned into L-glutamine so that it does not accidentally excite the next cell and send a false message.

In this way, a second and unwanted stimulation of the nerve cells can be avoided. Finally, L-glutamine is turned back into glutamic acid for the cycle to start again when needed.

As L-glutamine also has a certain anti-oxidative potential, it can protect human cells from destruction by free radicals. It is therefore able to, up to a certain point at least, prevent degenerative neurological illnesses like Alzheimer’s or Parkinson’s.

L-glutamine in use against illnesses

Autoimmune diseases in the digestive system like Crohn’s disease are almost always accompanied by reduced permeability of the intestinal wall. This ultimately leads to poor utilization of vitamins from the food you have eaten. Indian researchers have now proven that taking L-glutamine supplements as part of your diet (0.5g per kilo of body weight) can drastically increase intestinal permeability and thus improve the vital substances coming into your body2.

As well as this, bodily activity has an essential influence on generation of L-glutamine and also regulates its uptake.

It’s no wonder that you have depleted stocks of L-glutamine in your body if you push yourself to physical limits and have a difficult training programme – but this is associated with weaknesses in your immune system.

In order to avoid this consequence, L-glutamine supplements can be used, which will then improve the abilities of your immune system and stop inflammation at the same time3.

L-glutamine accompanying cancer treatment

blood capillary

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Another important field of application for L-glutamine in fighting illnesses is in cancer treatment. In the past, several studies were carried out, showing L-glutamine’s effects against tumours. 4

In their conclusions the researchers decided that appropriate L-glutamine supplementation can considerably improve the metabolism and entire clinical state of cancer patients without increasing tumour growth.

L-glutamine positively affects, among other things,

  • an increase of the immune system’s activity,
  • increased rate of cell renewal and,
  • a stronger creation of glutathione.

Furthermore, L-glutamine can lower the risks of chemotherapy and radiotherapy, leading to the patient being put under less strain.

Do not confuse L-glutamine and glutamate

Glutamate is a flavour enhancer mostly known for being from the Far East. As it is an edible product, it is permitted by many laws regulating nutrition in amounts up to 10g per kilo of food. Glutamate is the salt of glutamic acid. It is therefore chemically not comparable to, nor to be confused with, the amino acid L-glutamine.

As a food additive, the different forms of glutamate must be identified on packaging using the E-numbers E621 to E625. Companies prefer, however, to label their food with words like ‘spices’ or ‘yeast extract’, which is also permitted.

Allegedly toxic effects of glutamate in high doses have never been proven. In the 1940s children were administered with over 40g of glutamate per day over several months.

This was done under the belief that it could boost intellectual abilities.  Neither an intellectual increase nor long-term toxic effects could be proven by the study.


L-glutamine is indeed not an essential amino acid because the body can synthesis it, but it is popular  fields of sport and weight training to avoid the threat of muscle catabolism post workout. Among other things, L-glutamine is used to provide energy for all of your cells. It regulates the stability of acids and bases in the body and thus keeps proteins active. Due to its multitude of positive benefits, scientists have started to use L-glutamine in treatments of illnesses such as cancer and Crohn’s. It can efficiently and effectively alleviate symptoms and lead to a faster recovery.

Related studies:

  1. Matt Samuels, RD. “Glutamine and it’s Role in Athletic Performance” http://www.afpafitness.com/articles/articles-and-newletters/research-articles-index/nutrition-wellness/glutamine-and-its-role-in-athletic-performance/
  2. “Benjamin J et al.: Glutamine and whey proteine improve intestinal permeability and morphology in patients with Crohn´s disease: A randomized controlled trial; Dig Dis Sci, 2011 Oct 26”
  3. “Aostini, Francesco; Biolo, Gianni: Effect of physical activity on glutamine metabolism; Current Opinion in Clinical Nutrition & Metabolic Care; January 2010 – Volume 12 – Issue 1”
  4. “Katharina S Kuhn et al.: Glutamine as indispensable nutrient in oncology: experimental and clinical evidence; European Journal of Nutrition, Volume 49, Number 4/ Juni 2010”