Glutamine is the most abundant amino acid in the body, comprising more than 60% of the free amino acid pool in skeletal muscle and greater than 20% of total circulating amino acids. Supplemental L-Glutamine may help reduce muscle soreness and rebuild muscle tissue.

During stressful situations (i.e. heavy resistive weight training) the body can lose a large amount of glutamine. A loss of glutamine during exercise may be a signal for protein catabolism (muscle breakdown). Glutamine supplementation has been shown to prevent the loss of body mass through the positive role glutamine plays in protein synthesis and its action as a potent anabolic agent. When muscle glutamine levels are restored and in a positive nitrogen balance muscle synthesis can return to a normal rate.

Glutamine also has actions on glucose metabolism and the regulation of gluconeogenesis. Glutamine converts to glucose without changes in either insulin or glucagen, the hormones that regulate blood sugar. During dieting, and times of carbohydrate depletion, glutamine can exert positive effects on the amount of body fat loss as well as the retention of lean body mass.