L-Lysine Pro supports immune system function, eye and respiratory health. 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-arginine is required for the replication of the herpes virus. With twice the lysine of Vetri Lysine Plus, and the addition of DMG, L-Lysine Pro offers advanced support for cats.