Glutamine, or L-Glutamine, is an amino acid naturally found in meat and eggs. It is very often used as a dietary supplement to improve sports performance and strengthen the immune system. It is a non-essential amino acid, which means that the body can produce it from other amino acids found in the diet (in protein products such as meat, fish, eggs and vegetable proteins). It is the most common amino acid found in the body and muscles, regulates cell hydration and is effective in digestion problems (by improving the production of intestinal mucous membranes).
Among its supposed effects in relation to physical effort are:
- Improving exercise capacity
- Increased blood glucose and insulin
- Increased creatinine levels (this effect only occurs at high doses)
- The increase in uric acid and urea
- Decrease in Crohn’s disease symptoms
- Increased production of endogenous (growth hormone)
Its only proven effect is the decrease and increase of the blood ammonia level according to the dose consumed.
Glutamine is only rarely tested and no study guarantees positive long-term effects. It does not bring any benefit in the case of weight training. If there are any benefits, they are all related to the immune system and will not be used to improve sports performance or increase muscle mass.
Glutamine should not be used in cases of renal or hepatic insufficiency or in cases of predisposition to epilepsy (in this case glutamine may cause a decrease in the effect of drugs used to treat epilepsy). In general, glutamine is dangerous when taken in high doses, but there is no evidence that it is not safe even in low doses.