Alanine is an endogenous amino acid (i.e. having the ability to synthesize the human body other amino acids and pyruvate), building up protein. It has a key role in the transport of nitrogen between the muscles and the liver (i.e. Cahill cycle). It allows to transform glucose in non-sugar compounds. During prolonged exercise it enhances metabolism. It occurs in products of animal origin (meat, dairy, eggs) and vegetable origins (legumes, peas). It is used in the form of amino acid supplements in pre- and post-workout preparations. It complements the BCAA. Increased use of supplements with alanine is required in athletic training when high strength and endurance is required (e.g. weights lifting athletes marathon runners etc.).