L-Lysine Pro supports immune system function, eye and respiratory health in cats. As an important component of many proteins, L-lysine supports antibody, hormone and enzyme production. It also promotes healthy growth and development by supporting the production of collagen. L-lysine and the amino acid L-arginine compete for the same receptors in the body. L-Lysine competes with L-arginine, an amino acid responsible for upper respiratory issues. This formula also features DMG which has been shown to significantly increase immune response. These tasty chicken liver flavored-chews are made with hydrolyzed protein for cats with dietary sensitivities.