Dietary Supplement. Pure Free Form L-Glutamine Amino Acid Powder. Glutamine is the most abundant amino acid in your body, comprising more than 60% of the free amino acid pool in skeletal muscle and greater than 20% of total circulating amino acids. Each teaspoon of Optimum Nutrition's Glutamine Powder provides 4500 mg (4.5 g) of Pure L-Glutamine. Optimum Nutrition's Glutamine Powder is produced and packaged in our own state-of-the-art manufacturing facility. Optimum Nutrition is approved to manufacture Over-the-Counter (OTC) pharmaceuticals and operates in accordance with current Good Manufacturing Practices (cGMP's). Suitable for vegetarians.