Sale! Select options GXN (Greenex Nutrition) Active Glutamine Rated 5.00 out of 5 GXN Active Glutamine used to improve muscle growth and prevent muscle breakdown. Active Glutamine delivers the most abundant amino acid in the bloodstream is L-glutamine our body uses it in large amounts. Active Glutamine can be preferred to increase the athletic performance and may help in repair and recovery of broken muscle tissues. GXN Active Glutamine can be used for both weight loss as well as lean muscle growth.