Viralys is primarily used to support which system in cats?

Viralys is specifically formulated to support the immune system in cats. It contains L-lysine, an amino acid that is known for its antiviral properties, particularly against feline herpesvirus, a common viral infection in cats. By boosting the immune response, L-lysine helps prevent viral replication and assists the cat's body in managing and preventing infections.

In the context of the other systems listed, Viralys does not primarily function to aid the digestive, endocrine, or cardiovascular systems. While those systems are crucial to overall health, the primary indication of Viralys is focused on enhancing immune function, making it an important tool for maintaining the health of cats, particularly those that are prone to viral infections.