Use of Lysine in FIP – Drugon Biotech

DRUGON BIOTECH

L-lysine is often recommended for cats, particularly for managing feline herpesvirus (FHV-1), a common respiratory infection in cats, not for FIP. First, let's clarify:

Feline Herpesvirus (FHV-1): FHV-1 is a virus belonging to the herpesviridae family and typically causes upper respiratory infections, eye inflammation, and sometimes skin lesions. This virus can become active especially in cats under stress or with weakened immune systems.
Feline Infectious Peritonitis (FIP) Virus: The FIP virus belongs to the coronaviridae family and usually affects young or immunocompromised cats. This virus causes inflammation in various organs of the body and is often a severe and fatal disease.

Therefore, these two viruses belong to different families.
Now, let's discuss the benefits of Lysine:

1. Inhibition of Viral Replication:

L-lysine is believed to inhibit the replication of FHV-1. The virus needs another amino acid, arginine, to replicate. L-lysine competes with arginine, potentially reducing the virus's ability to multiply. Although it is a common belief that L-lysine inhibits the replication of FHV-1 by lowering arginine levels, studies have shown that L-lysine does not possess antiviral properties in this context. The study "Effects of L-lysine and L-arginine on in vitro replication of feline herpesvirus type-1" found that L-lysine supplementation attenuates the growth-promoting effect of arginine in environments with low arginine concentrations.

(Maggs, D. J., Collins, B. K., Thorne, J. G., & Nasisse, M. P. (2000). Effects of L-lysine and L-arginine on in vitro replication of feline herpesvirus type-1. American journal of veterinary research, 61(12), 1474–1478. https://doi.org/10.2460/ajvr.2000.61.1474)

However, another study indicated that various concentrations of L-lysine did not inhibit the in vitro replication of FHV-1 at arginine concentrations sufficient to maintain cell growth.

(Cave, N. J., Dennis, K., Gopakumar, G., & Dunowska, M. (2014). Effects of physiologic concentrations of l-lysine on in vitro replication of feline herpesvirus 1. American journal of veterinary research, 75(6), 572–580. https://doi.org/10.2460/ajvr.75.6.572)

2. Reduction of Symptoms:

Regular administration of L-lysine can help reduce the severity and frequency of herpes flare-ups in cats. This includes symptoms like sneezing, conjunctivitis, and discharge from eyes or nose. The study "Efficacy of oral supplementation with L-lysine in cats latently infected with feline herpesvirus" examined the effects of orally administered L-lysine on the clinical signs of FHV-1 infection and ocular shedding of the virus in latently infected cats. The study found that fewer cats and eyes were affected by conjunctivitis, and the onset of clinical signs of infection was delayed on average by 7 days in cats receiving L-lysine, but significant differences between groups were not demonstrated.

(Maggs, D. J., Nasisse, M. P., & Kass, P. H. (2003). Efficacy of oral supplementation with L-lysine in cats latently infected with feline herpesvirus. American journal of veterinary research, 64(1), 37-42.)

3. Supporting Immune Function:

L-lysine plays a role in antibody production and possesses various immune-boosting properties. It aids in the formation of collagen, which is important for healthy skin and mucous membranes. Healthy mucous membranes are fundamental for defense against pathogens. The same study mentioned above suggests a potential role in enhancing immune response against FHV-1, showing a decrease in virus spread in cats treated with L-lysine. However, the study did not find significant changes in plasma arginine concentrations.

4. Safety and Tolerance: Generally, L-lysine is well tolerated by cats and can be given for a long time for chronic conditions like FHV-1. A comprehensive review titled "Comprehensive Safety Assessment of l-Lysine Supplementation from Clinical Studies: A Systematic Review" evaluated the clinical safety of l-lysine supplementation. The review included various studies and found that most observed adverse effects were subjective gastrointestinal symptoms, and the risk analysis for the incidence of these symptoms was not statistically significant. This indicates that l-lysine is relatively safe at certain doses.

(Hayamizu, K., Oshima, I., & Nakano, M. (2020). Comprehensive Safety Assessment of l-Lysine Supplementation from Clinical Studies: A Systematic Review. The Journal of nutrition, 150(Suppl 1), 2561S–2569S. https://doi.org/10.1093/jn/nxaa218).

There is no academic research on the effects of Lysine supplementation in relation to FIP in cats. Only the following 2 separate studies have stated findings that it is ineffective in FHV-1 infection and these studies have not been subsequently confirmed by other studies.

The only two articles that state it is not beneficial (there is no statement that it has a negative effect) are;

1. Bol, S., Bunnik, E.M. Lysine supplementation is not effective for the prevention or treatment of feline herpesvirus 1 infection in cats: a systematic review. BMC Vet Res 11, 284 (2015). https://doi.org/10.1186/s12917-015-0594-3

2. Drazenovich, T. L., Fascetti, A. J., Westermeyer, H. D., Sykes, J. E., Bannasch, M. J., Kass, P. H., ... & Maggs, D. J. (2009). Effects of dietary lysine supplementation on upper respiratory and ocular disease and detection of infectious organisms in cats within an animal shelter. American Journal of Veterinary Research, 70(11), 1391-1400.

Another page presented as evidence,

https://fipcaregroup.com/pages/l-lysine-FIP-cats.html,

emphasizes that Lysine-containing products should definitely not be used in cats for FIP treatment, citing only the above-mentioned two studies that state there is no extra healing effect of Lysine in FHV-1.

In summary, it is important to note that these results are based on theoretical understanding and anecdotal evidence of how L-lysine and arginine interact. These results are built on general ideas of how these interactions might occur, rather than direct scientific studies focusing on the effects of L-lysine in FIP treatment. There is NO academic study that necessitates the absolute avoidance of Lysine in cats, especially in FIP infection. Our product contains Lysine formulated to display its general immune-boosting effects without the possibility of creating a negative situation in cats with FIP by competing with Arginine, and we particularly want to emphasize this without basing it on this new clinical myth.