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Lysine for Cats

Posted: 04/29/2024 | BY: Jenna Bruce | Categories: Cat , Health problems

Cats provide companionship, entertainment, and much-needed stress relief. Plus their curious antics make us wonder and laugh out loud. So we want to do everything we can to keep them healthy. Lysine for cats is one of the best ways to support their immune system and lessen upper respiratory symptoms such as sneezing, congestion, and runny or red eyes. 

In this blog post, we’ll discuss what lysine is, what it can do for your cat, and dosage recommendations.

What Is Lysine?

Lysine, or L-lysine, is an essential amino acid. If you remember back to biology class, amino acids are the building blocks of proteins in the body. In cats, this particular amino acid is used to treat the clinical signs associated with feline herpes virus infections. 

Lysine is sold as a supplement and usually found at your local pet stores or online. While pet supplements are sold over the counter, it is still advised that you consult your veterinarian before giving your cat lysine to help treat viral symptoms. 

How Does Lysine Work?

In cats, L-lysine is believed to slow down the replication of feline herpesvirus-1 (FHV-1). This is what cat parents tend to call a “cat cold” because the symptoms are similar to human colds, mainly sneezing, nose and eye discharge, and conjunctivitis. 

The FHV-1 virus needs another amino acid called arginine to be able to replicate inside your cat’s body and cause disease. Lysine coats the herpesvirus, prohibiting arginine from replicating the virus. Without viral replication, the symptoms of FHV-1 lessen and resolve much quicker.

How Effective is Lysine?

That’s a tricky question to answer as there is limited data. Historically, veterinarians have recommended lysine for cats to help combat the symptoms of feline herpes virus. And there is anecdotal evidence that suggests lysine does in fact suppress symptoms. 

That being said, there have been recent studies that suggest lysine is not effective in stopping the spread of infections in shelters, catteries, or multi-cat households. So if you have a multi-cat household, the lysine may help all of your babies feel better sooner, but it may not stop the cat that always sneezes first passing it on to others.

How to Give a Cat Lysine

Lysine supplements come in powders, pastes, gels and treats. Powders are easy because you can mix them right into your cat’s wet food and they don’t even know it’s there. Many cats enjoy the lysine treats while others take to the tasty gel or paste. You’ll really need to see which your cat(s) like best.

Again we want to mention that before giving your cat any new supplement, always speak with your veterinarian first. If your cat is experiencing upper respiratory symptoms, lysine may help but may not be the only treatment needed. 

Are There Any Side Effects in Lysine for Cats?

There are no known side effects of lysine supplementation in cats in healthy cats. Lysine is a short-acting supplement and would be out of the bloodstream within 24 hours. Effects of the supplement can remain longer in cats with liver or kidney disease.

And, as with any supplement or medication, use cautiously in pregnant or lactating cats as studies are limited in this population. 

Are there any drug interactions I should be aware of?

Lysine may interact with arginine and oral calcium supplements. Be sure to tell your veterinarian about any medications, vitamins, or supplements your pet is taking before giving them lysine.

Final Thoughts

Lysine for cats has been shown to help decrease the symptoms of the herpes virus. It may not be enough to prevent the spread of infection between cats in a multi-cat household, however.

If your cat is experiencing respiratory symptoms, schedule an appointment to see your veterinarian. They may need more medical attention than what lysine can provide. 

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  3. Bol S, Bunnik EM. Lysine supplementation is not effective for the prevention or treatment of feline herpesvirus 1 infection in cats: a systematic review. BMC Vet Res. 2015 Nov 16;11:284. doi: 10.1186/s12917-015-0594-3. PMID: 26573523; PMCID: PMC4647294.



The information contained on this blog is intended for informational and educational purposes only and should not be construed as medical advice. It is not a substitute for professional veterinary care. Always consult with your veterinarian before making any changes to your pet's health care or treatment plan.

The authors of this blog are not veterinarians and do not claim to be experts in pet health. The information provided here is based on our own experiences and research, as well as information from reputable sources. However, we cannot guarantee the accuracy or completeness of this information.

We encourage you to do your own research and consult with your veterinarian before making any decisions about your pet's health.

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