Nutrition Muscle Tissue Gluten Free Amino Acid Dietary Supplement Most abundant amino acid in the human body. Jarrow Formulas L-Glutamine is manufactured by microbial fermentation. L-Glutamine is the most abundant amino acid in the human body and is involved in many metabolic processes, including the synthesis and protection of muscle tissue, the production of glycogen, and provide immune support during periods of immune and muscular stress. L-Glutamine is also a major source of fuel for enterocytes (intestinal cells) and hence supports the integrity of the intestinal lining.