Vetoquinol Viralys L-Lysine Supplement for Cats & Kittens (Fish-Flavored Powder)

Viralys L-Lysine for Cats | Eye, Respiratory & Immune Support, Fish-Flavored Powder

Quick Facts:

• Active ingredient: L-Lysine HCl
• Used for: Feline herpesvirus (FHV-1) symptom support — eye discharge, sneezing, respiratory issues
• Species: Cats and kittens
• Format: Fish/poultry-flavored oral powder, mixed into food twice daily
• Consult a vet if: Symptoms persist beyond a few days or worsen
• Ideal for: Cats with recurring upper respiratory or eye symptoms linked to feline herpesvirus

Description: Viralys is built around a specific, well-documented use case: supporting cats with feline herpesvirus (FHV-1), a common cause of upper respiratory symptoms and eye discharge, especially in cats from shelters or multi-cat households. Research cited by the manufacturer found that oral administration of 500 mg of lysine resulted in less severe conjunctivitis symptoms caused by FHV-1, which is the basis for the supplement's targeted eye, respiratory, and immune claims. The fish and poultry-flavored powder is designed to be palatable even for picky cats, and is meant to be mixed into wet or dry food twice daily — the label recommends 250 mg twice daily for kittens under 6 months and 500 mg twice daily for cats 6 months and older, though owners should confirm dosing with their veterinarian. Vetoquinol also offers Viralys in gel and chew formats for cats that resist powder mixed into food. As a nutritional supplement rather than a prescription antiviral, Viralys is generally used as ongoing daily support rather than a one-time treatment, and persistent or worsening respiratory or eye symptoms still warrant a veterinary exam to rule out secondary infection.