Glutamine is the most abundant, naturally occurring amino acid in the human body. It constitutes more than 60% of the amino acids found in skeletal muscle and is the most concentrated free amino acid in the blood. Glutamine can be used as a building block for making more proteins (i.e. muscle), a direct energy source for making ATP (the energy currency of the body) or as a precursor for the formation of glucose in the liver.
While skeletal muscle tissue is responsible for synthesizing ~90% of the glutamine found in the body, the most eager consumers of glutamine are the gut, kidneys and immune system. Glutamine therefore, may be supportive for a variety of biochemical functions ranging from protein synthesis to intestinal permeability, optimal immune function and the regulation of the body’s acid-base balance.
Importantly, glutamine is considered a conditionally essential amino acid meaning it may be more important when undergoing the stress of regular intense exercise and food restriction.