Glutamine benefits have been studied extensively over the past 15 years, and its use has been shown to be useful in treatment of various trauma, injuries, burns and wound healing. It is also used in treatment of some cancer related side effects. Glutamine is also extensively used in bodybuilding world. It is marketed as a supplement used for muscle growth.
Benefits of glutamine supplementation on growth hormone secretion
It has been noted in the literature that glutamine might increase plasma arginine and glutamate concentrations, amino acids both with the potential to increase growth hormone secretion . In the light of this, Thomas C. Welbourne and assistants  wanted to determine whether oral glutamine supplementation can increase plasma glutamine and if that increase is sufficient to increase plasma growth hormone concentrations. Nine healthy subjects (32-64 year old) ingested 2 grams of L-glutamine. Surprisingly, a small dose of L-glutamine was able to elevate circulating plasma glutamine, which indicated that significant amount of orally loaded glutamine reached periphery. Larger doses further increases plasma glutamine, while doses lower than 1 gram might be unable to significantly elevate plasma glutamine. The rise of growth hormone occurred 90 minutes after oral ingestion in seven out of eight subjects and it exceeded the time control value by 4-fold. However, one hour of high intensity exercise can result in a 20-fold increase in plasma growth hormone concentration, so this is not a reason for athletes engaged in exercise training to take glutamine supplements .
- Alba-Roth, Julia., et al. “Arginine stimulates growth hormone secretion by suppressing endogenous somatostatin secretion.” Journal of Clinical Endocrinology & Metabolism 67.6 (1988): 1186-1189.
- Welbourne, T. C., et al. “Increased plasma bicarbonate and growth hormone after an oral glutamine load”. The American journal of clinical nutrition 61 (5) (1995): 1058–1061.
- Gleeson M. et al. “Dosing and efficacy of glutamine supplementation in human exercise and sport training.” J Nutr. 2008;138:2045–9.