Active amino acid content Mega capsule packaging. Arginine is an amino acid that is made in the pituitary gland. This means that arginine is not an essential nutrient, but during a higher load your body may not be able to produce it in adequate amounts. Arginine plays a very important role in the synthesis of nitric oxide, also known as nitrogen monoxide or NO. 1 serving (1 capsule): 825 mg of L-arginine HCl We recommend the L-arginine capsule if: you practice endurance sports, to take before training is bodybuilder sensitive to additives Like all BioTech USA products, the L-arginine capsule is made up of safe and carefully selected ingredients.