Cat L-Lysine Powder

Feline herpesvirus type 1 (FHV-1) is one of the most common infections in cats — especially those who came from shelters. Once a cat is infected, the virus stays in their system for life. Symptoms like goopy eyes, sneezing, and upper respiratory flare-ups can come and go, often triggered by stress or a weakened immune system. There is no cure, but daily L-Lysine supplementation helps support your cat's immune response and reduce the frequency and severity of flare-ups.

FHV-1 depends on another amino acid called arginine to replicate inside your cat's body. L-Lysine competes with arginine, which can interfere with the virus's ability to replicate and spread. When the virus has less opportunity to replicate, your cat experiences fewer and less severe flare-ups — which means clearer eyes, less sneezing, and more comfortable days.

Most cat owners start noticing a difference within 2 to 4 weeks of daily use. Because FHV-1 is a chronic condition, consistent daily supplementation gives the best results. Many owners report the biggest improvement after 30 to 60 days of continuous use. We recommend trying a full 60-day supply before evaluating — that's why we offer a 30-day money back guarantee.

Yes — even picky cats. The powder is completely tasteless and blends invisibly into wet or dry food. Your cat won't detect it at all — just mix it in and they eat it like normal. Even picky cats have no idea it's there.

One scoop per day, every day, mixed into food. Each scoop delivers 900mg of L-Lysine — the vet-recommended daily amount. The measuring scoop is included in every jar. For kittens under 6 months, use half a scoop. For cats over 10lbs, you can use one and a half scoops if needed.

Yes. L-Lysine has an excellent safety profile and is well tolerated in cats of all ages. Because FHV-1 is a lifelong condition, long-term daily supplementation is both safe and recommended. The formula contains no soy, no corn, and no artificial ingredients — just clean, third-party tested ingredients made in the USA.

L-Lysine is a dietary supplement and is generally compatible with other treatments. If your cat is on prescription medication, we recommend checking with your vet before adding any new supplement to their routine. That said, L-Lysine is widely used alongside standard veterinary care for FHV-1.

Every cat is different. If you don't see improvement after giving it a full 60-day trial, just reach out within 90 days of your purchase for a full refund — no questions asked, no hassle. We only want to keep your money if your cat actually benefits.