Marketing materials often present glutamine as amino acid, which is essential for efficient development of muscle strength and mass, as well as for proper functioning of the body, when supplied with food or in a form of supplement. Therefore, many people buy and use products containing glutamine believing that they are improving their sports form and health. But are they right? Well, this subject seems to be quite complicated.
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When there are slogans in the marketing materials suggesting that glutamine is an essential amino acid for physically acitve people, there is double misunderstanding in it. First of all, the phrase “essential” is a professional word. Amino acids, which form proteins are divided into groups depending on the fact if the body is able to synthesise them or not – which is why they have to be provided from outside. Amino acids from the first group are called endogenic, the others are included in the exogenous group, i.e. they are essential. It's good to know that glutamine belongs to the first group of amino acids, which means it is not essential – the body is able to synthesise it from other amino acids and does it so easily that glutamine is also not included in the group of relatively exogenous amino acids...
Glutamine and the development of muscle mass
From the muscle mass development point of view, the availability of the exogenous, i.e. essential, amino acids is the most important. We also know that glutamine does not belong to this group, but does it mean that its intake has no influence on the synthesis of muscle proteins? Well, if you look at the results of scientific studies, you will find out that there are various outcomes. However, there are more of those, which show no influence of such amino acid on that process. According to the statement that “who seeks the truth, should not count votes”, you should pay attention to the methodology of the available studies, and here it turns out that those, in which glutamine showed the pro-anabolic result, were done on people in hospitals, ill, after various procedures and injuries. In case of sports people, the positive influence was rather episodic. In the independent studies, the outcome of glutamine was rather poor, which can be noticed in the study linked below:
Glutamine and muscle catabolism
The study cited above also indicates that the activity of glutamine is not particularly special when it comes to its influence on muscle catabolism. Theoretically, or rather – according to the guarantee of the diet supplements producers – this amino acid should protect the muscles from proteolysis connected with physical effort, but it doesn't happen in reality. In the study mentioned above, there was no significant influence of 0.9g of glutamine per 1 kg of lean body mass on the level of 3-methylhistidine in urine (the catabolism marker) comparing to placebo. However, on the other hand, on the basis of that data, the enthusiasts of glutamine could formulate the thesis claiming that this amino acid shows some anti-catabolic potential, because the placebo was “sports sugar”, i.e. maltodextrin. Even when following this path, it should be stated that the observed anti-catabolic activity of glutamine is similar to that of sugar.
Glutamine and muscle strength
If glutamine is not anabolic, or anti-catabolic, maybe it supports the development of effort abilities, such as muscle strenght? Well, there isn't any good news in this matter, too. Scientific studies don't support the common theory, according to which glutamine improves the results of the biathlonists or powerlifters. The example, which proves lack of the ergogenic potential of glutamine may be a double-blinded, controlled test on sports people, in which the intake of 0.3g of glutamine per 1 kg of body mass didn't cause better results than placebo. You can read more about it in the text linked below: