1. What is it and where does it come from?
The extremely popular amino acid L-Glutamine can be found in protein powders, beans, meats, fish, poultry, dairy products, and of course, L-Glutamine supplements from Bodybuilding.com.
2. What does it do and what scientific studies give evidence to support this?
Glutamine is highly in demand throughout the body. It is used in the gut and immune system extensively to maintain optimal performance.* 60% of free-form amino acids floating in skeletal muscles is L-glutamine. L-glutamine plays a very important role in protein metabolism, and it appears to be a very important nutrient for body builders.* When supplemented, it may help body builders reduce the amount of muscle deterioration that occurs because other tissues that need glutamine will not rob the glutamine stored in the muscle cells.*
Research suggests that after intensely working out, glutamine levels in the body are reduced by as much as 50%.* Since the body relies on glutamine as cellular fuel for the immune system, scientific studies suggest that glutamine supplementation can minimize the breakdown of muscle tissue and improve protein metabolism.* Glutamine's cell-volumizing effects have also been supported by several studies.* No conclusive studies have been done to evaluate the effects of L-glutamine supplementation on weight-training adults; however, a recent study suggests a meaningful increase in growth-hormone levels when as little as 2 grams of free-form L-glutamine supplement was consumed!*
3. Who needs it and what are some symptoms of deficiency?
Bodybuilders can particularly gain from the intake of glutamine. Since bodybuilders use a lot of their glutamine when working out, the immune system relies heavily on this amino acid.*
Catabolism or muscle break down can occur if the body robs muscles of glutamine for use elsewhere such as nitrogen transport or maintaining the immune system. Glutamine supplementation is certainly important in keeping muscles building--not deteriorating.*
4. How much should be taken? Are there any side effects?
Reports of an upset stomach are associated with ingesting large quantities of glutamine; using smaller doses is recommended if this occurs. Always consult the manufacturer's labeling for instructions on proper supplement dosage.