L-Lysine Supplement for Cats L-lysine's mechanisms of action are rooted in its role as an amino acid. Amino acids are the building blocks of proteins and are involved in various biochemical processes within the body. L-lysine specifically supports the synthesis of proteins involved in the immune response, collagen formation, and the regulation of calcium. L-lysine supplementation can reduce the severity and duration of symptoms such as sneezing, nasal discharge, and eye discharge. L-lysine is also involved in the absorption of calcium, which is essential for bone health. It in the regulation of calcium levels in the body and supports proper bone development. This aspect is particularly relevant for growing kittens and for older cats, as it helps maintain bone density and overall skeletal health.