Lysine for Cats

Posted by Dr. Roth on

Lysine for Cats

Like humans, cats can develop viral and bacterial infections that affect their immune system and respiratory health. Along with providing rest and proper veterinary care, pet parents can help boost their cat's health by changing their diet. Supporting their diet with lysine amino acid and other cat health supplements may also help maintain a pet's immune system and lessen symptoms. 

Pet parents unfamiliar with lysine for cats may be wondering how lysine supplements can help their pets and what they should know about benefits and considerations. 

A Cat's Diet

Cats are carnivores, and they need to get their nutrients from meat. Calcium, niacin, and vitamin A are especially important for cats, but so are essential amino acids like taurine, arginine, lysine, and eight others. These 11 amino acids are considered essential because they must come from food, and a cat's body can't make them. 

Nutrient quantity is also important. Cats require different levels of amino acids than other pets, such as dogs. Too much could lead to toxicity, and too little could lead to a deficiency or illness. 

Since cats can't convert plant-based proteins and amino acids into a usable form, they must get them from meat proteins. 

An Overview of Lysine for Cats

Lysine, also called L-lysine, is an essential amino acid for cat health. It helps build antibodies and enzymes that strengthen the immune system. This amino acid also helps cats absorb calcium for stronger teeth and bones, and it plays a role in collagen production and healthy skin. When cats don't get enough lysine in their diet, they can't be as healthy and may have a higher risk for infection, especially in the upper respiratory tract. 

This amino acid is readily found in meat proteins, with the highest concentrations in red meat, pork, poultry, and fish like cod and sardines.

Lysine as a Supplement

Pet parents want the best for their pets, including a healthy diet. Sometimes, a healthy diet alone can't give cats the nutrients they need to thrive. That's when pet parents ask about supplements. 

Lysine supplements typically come in powders, tablets, or gels. While the powders and tablets are taken with food, the gels may be taken on their own, depending on a cat's preferences.

Daily powders and oral gels can help support a cat's immune system, including eye and respiratory health. To give their cats a lysine supplement, pet parents might sprinkle the powder over dry kibble or mix it into wet canned food. Lysine powder for cats can be easier to incorporate because it blends well with most cat food. The oral gel may not work as well with dry kibble, but it makes an excellent addition to wet canned food because of its similar texture.


Supplement side effects aren't common, although pet parents should only give lysine supplements as directed by their pet's veterinarian. 

Pet parents can also consider lysine treats for cats. Cat lysine chews have the recommended amount of lysine supplement and feature pleasing, savory meat flavors that cats love. 

Lysine and the Feline Herpesvirus

Feline herpesvirus type 1, or FHV-1, goes by feline viral rhinotracheitis or FVR. The feline herpesvirus infects a cat's upper respiratory tract, causing fever, sneezing, sinus congestion, and conjunctivitis, including eye inflammation and discharge. 

Since FHV spreads easily, it can infect a multiple-cat household in days. According to Cornell College of Veterinary Medicine, as many as 97% of cats are exposed to the virus in their lifetime with 80% of those exposed developing lifelong infections. Stress is one of the most common causes of feline herpes flare-ups. Unfortunately, when cats shed the virus periodically, they expose other cats to potential infection. 

Some veterinary professionals recommend lysine supplements to reduce symptoms and help strengthen a cat's immune system to fight the virus. There is much debate about using lysine supplements for an FHV infection, with some studies showing its benefits and other studies having mixed results

Although lysine for an FHV infection has mixed opinions, the amino acid itself remains a vital part of a cat's nutritional needs. Whether in the normal diet or as a supplement for cat health, lysine helps support the immune system, bones, eyes, skin, and other body functions.

Advice From Fuzzy Vets

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