Lysine in herpes virus for cats

L-Lysine to use or not to use?

L-Lysine supplements in cats, to use or not to use… that is the question?

For years now veterinarians and cat breeders alike have been touting the benefits and importance of using L-lysine to help combat the symptoms and outbreaks of the herpes virus in cats.  However, after years of recommendations and dedicated use, new research is showing that there in fact is no evidence that it is helpful against the feline herpes virus and may in fact be harmful to overall feline health.


What is L-lysine?

L-Lysine is an essential amino acid found in food as well as in supplement form.  It is one of many amino acids, also known as the “building blocks of protein,” which is responsible for sustaining good health by facilitating thousands of necessary bodily functions.  In addition to supplement form, lysine is found in many foods including meat, beans, cheese, and eggs. 

One of the ways that lysine is most important is in the creation of carnitine which works in the body to converting fatty acids into energy.  It also plays a role in absorbing calcium for the body to utilize, as well as aids in the production of the bodies’ collagen.



It has been well documented and experienced in humans that lysine does in fact have some positive effects on the herpes simplex 1 virus.  It has been shown to both reduce the number of outbreaks of cold sores, and also to shorten the duration of time of the outbreak.  The reasoning behind this effect is that lysine is known to lower the natural levels of arginine in the body which help the herpes virus to replicate.  Therefore, higher levels of lysine, equal in turn, lower levels of arginine which reduce the rate of duplication of the virus. However, this effectiveness does not transfer over to cats; it doesn’t appear that the levels of arginine directly affect the feline herpes virus.



There has not been much in the way of studies performed on lysine and its effects in cats, however there have been a few animal studies which look at the effects of high lysine levels in the diet in chickens, dogs and rats.  In each study lysine was added to the diet in the animals during the growth phase which resulted in low weight, and a reduced growth weight of the animals which was restored when the plasma lysine levels were restored to normal.

There has also been a study conducted in vitro on the feline herpes virus which was exposed to lysine and the results showed no reduction in the rate of growth of the virus within the feline cells being studied.


Recommended Discontinuation of Use

Based on the lack of evidence for effectiveness, as well as the potential effects of negative health benefits of use of lysine supplementation in cats, the NIH (National Institutes of Health) has made the following statement regarding recommendation of use: “We recommend an immediate stop the use of L-lysine supplementation [in cats] because of the complete lack of any scientific evidence for its efficacy.”

Based on this newly discovered information, LiLNudists Cattery as well will no longer recommend the use of L-lysine supplements in our cats or kittens. 


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Please note: This article has been provided for informational purposes only. If your pet is showing any signs of illness, please consult a veterinarian as quickly as possible. A raw food diet may not be appropriate for all cats in all stages of health and we always recommend having your cat examined and discussing diet changes with your veterinarian.


Keep those Hairless Kitties Healthy and Happy Everyone!!!


Text: Copyright © April Arguin RDH, Founder of LiLNudists Sphynx & Bambino Cattery. All rights reserved.






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