L-Glutamine, commonly referred to as a conditionally essential amino acid, is the most abundant amino acid in the body (including the brain, muscle and blood). In muscle, the concentration of free glutamine appears to influence whether muscle will be broken down (catabolism-low glutamine content) or built up (anabolism-high glutamine content). Glutamine acts as a nitrogen shuttle by picking up and dropping off nitrogen around the body. Nitrogen is an essential component of DNA, and vital for building muscle. Glutamine is a prominent contributor to the functional integrity of the intestines and serves as an energy source for these highly active cells. Glutamine is pivotal in supporting your body's defense against foreign challenges.