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9 Best Lysine Supplements for Cats – 2024 Reviews & Top Picks

Ashley Bates

By Ashley Bates

Vet approved

Dr. Paola Cuevas Photo

Reviewed & Fact-Checked By

Dr. Paola Cuevas

MVZ (Veterinarian)

The information is current and up-to-date in accordance with the latest veterinarian research.

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Blue-eyed tabby cat

Did you know that lysine can boost the immune system of both humans and other mammals, including domesticated pets like cats? Lots of cats have issues with health and low immunity, so supplements are a good thing to try when your cat isn’t feeling 100%.

We compiled these reviews on cat lysine products, and think we’ve found a product to match every feline need from liquid to chews to powder. Take a look at these great selections to see which works best for your feline friend.

Note: While lysine can really help boost immunity, we recommend always checking with your vet before adding any supplements to your cat’s diet.


A Glance at Our Favorites in 2024

Rating Image Product Details
Best Overall
VetriScience Vetri Lysine Supplement VetriScience Vetri Lysine Supplement
  • Added DMG
  • Added antioxidants
  • Terrific for any life stage
  • Best Value
    Second place
    Duralactin Feline L-lysine Cat Supplement Duralactin Feline L-lysine Cat Supplement
  • Affordable
  • Added omega fatty acids
  • Easily measurable servings
  • Premium Choice
    Third place
    Vetoquinol Viralys L-lysine Oral Gel Vetoquinol Viralys L-lysine Oral Gel
  • Made in the USA
  • Gel + chew combo
  • Great for multi-cats
  • Alpha Paw Cat L-Lysine Supplement Alpha Paw Cat L-Lysine Supplement
  • For indoor/outdoor cats and kittens
  • 100% lysine
  • No taste, undetectable in food
  • Strawfield Pets L-lysine Support Strawfield Pets L-lysine Support
  • Works to prevent infections
  • Chicken flavor with no fillers
  • Easy to add to foods
  • The 9 Best Lysine Supplements for Cats

    1. VetriScience Laboratories Vetri Lysine Plus – Best Overall

    VetriScience Laboratories Vetri Lysine Plus

    Supplement Type: Chews

    Of all lysine products for cats, VetriScience Laboratories Vetri Lysine Plus was our favorite overall. It supports immunity, vision, and the respiratory system. You can protect your feline and strengthen their bodies to stay their healthiest. These supplements come in the form of 120 chicken-flavored fish-shaped chews. Cats seem to enjoy the flavor, so they will be a handy daily treat your cats can look forward to.

    Not only does it have L-lysine for immunity, but there is also added DMG for hormone and antibody-building support. These amino acids help repair tissue and support collagen formation and enzymatic functions that play an important role in the immune system.

    This recipe is designed for multi-cat households of any life stage—from kittens to seniors. Since it meets the needs of almost all house cats, we think you will approve of this product. However, it won’t work for every cat due to dietary restrictions, so make sure to check all ingredients.

    • Added DMG
    • Supports antibody building
    • Supports enzymatic functions
    • Formula suitable for kittens, adult, and senior cats

    • Some ingredients might not work for every cat

    2. Duralactin Feline L-lysine Cat Supplement – Best Value

    Duralactin Feline L-lysine Cat Supplemen copy


    Supplement Type: Liquid

    If you’re looking to save a few dollars but still want total immunity support for your cat, think about Duralactin Feline L-lysine Cat Supplement for cats. It’s the best lysine supplement for cats for the money. This supplement comes in liquid form in a syringe. It has easy-to-read measurements on the side so you can get the perfect amount with each application. You simply add this liquid to your cat’s or kitten’s daily meal.

    It directly targets immune support with a few added perks. On top of immune support, this supplement has added omega fatty acids to nourish your cat’s skin and coat.

    For the price, we think this is a terrific product for every life stage. Of course, some finicky cats might disapprove of this new addition to their daily chow. Also, the seal isn’t perfect on the syringe, so there could be a chance of slow leaking. Those things aside, it’s worth trying out, especially for the price.

    • Affordable
    • Added omega fatty acids
    • Easily measurable servings

    • Syringe might leak

    3. Vetoquinol Viralys L-lysine Oral Gel – Premium Choice

    Vetoquinol Viralys L-lysine Oral Gel

    Supplement Type: Oral gel, chews

    The Vetoquinol Viralys L-lysine Oral Gel might be a tad pricey, but we think it’s definitely worth the investment. If you know your cat benefits from these dietary specifications, it is a pretty big bang for your buck, coming in both oral gel and chews in one order.

    The flavor of the chicken liver chews is cat-approved. Both products are designed to lessen symptoms related to respiratory trouble and strengthen overall immunity. In addition, it reduces eye inflammation, and conjunctivitis, and clears the sinuses. Ultimately, we found this product was especially useful for cats who continually have gunk in their eyes and ones who sneeze regularly. Granted, it can really boost the immunity of nearly any house cat.

    We found this would be especially good for multi-cat households where each preferred a different method of ingestion. Each product is made in the USA.

    • Made in the USA
    • Gel + chew combo
    • Great for multi-cats

    • Pricey

    4. Alpha Paw Cat L-Lysine Powder Supplement – Best for Kittens

    Alpha Paw Cat L-Lysine Powder Supplement

    Supplement Type: Powder

    If you have a kitten, the Alpha Paw Cat L-lysine Powder Supplement might work wonders. This human-grade supplement is terrific for kittens because you can blend it into their regular diet without them catching on.

    This product doesn’t beat around the bush or tack on extras—it’s 100% lysine for maximum benefits. It also works wonders for picky cats—and indoor/outdoor dwellers, so everyone benefits. It’s totally tasteless and odorless, so it’s completely undetectable in food. This formula clears up a lot of the eye gunk you see in litters of kittens sometimes. Plus, it strengthens their immunity to better fight these bacterial buildups.

    However, if you need additional support for your cat through other additives, pure lysine might not work in this situation. You might want to check out other avenues.

    • For indoor/outdoor cats and kittens
    • 100% lysine
    • No taste, undetectable in food

    • Pure lysine won’t work in all situations

    5. Strawfield Pets L-lysine Immune Support for Cats

    Strawfield Pets L-lysine Immune Support

    Supplement Type: Powder

    Strawfield Pets L-lysine Immune Support is a powder supplement formulated to reduce symptoms of feline herpes and boost immunity. This recipe contains high-quality ingredients that are sure to benefit your cat overall. This product is perfect for treating and preventing infections. It contains no fillers, so it would be a great option for cats with dietary sensitivities. It’s also useful for cats of all life stages, so it will work for every kitty in your home.

    You can add this supplement to meals easily by adding one scoop into their loaf or dry kibble. Mix or shake the food until the formula dissolves. It’s chicken-flavored so it will mix right in with their existing diet without them even knowing it.

    Even though this product is meat-flavored, some kitties might not be fooled. If your cat snubs the taste, you might need to look for tasteless powders instead.

    • Works to prevent infections
    • Chicken flavor with no fillers
    • Easy to add to foods

    • Some cats might not enjoy the taste

    6. Coco & Luna L-lysine Powder for Cats

    Coco and Luna L-lysine Powder for Dogs & Cats

    Supplement Type: Powder

    If you share your home with dogs and cats alike, both species can benefit from Coco and Luna L-lysine Powder for Dogs and Cats. So, we suggest this product for multi-pet households who need an immunity health booster. This product is a powder supplement, so you can just add the recommended dose to your pet’s food bowls and call it a day. It’s salmon-flavored, so it’s sure to get your kitty’s attention. The recipe is non-GMO with 100% premium quality—guaranteed.

    This formula combats itchy eyes, inflammation, respiratory support, and general wellness. If you aren’t satisfied with the product for any reason, the company will work to make it right.

    Even though this product works for both cats and dogs, you might not need that extra perk. Since it’s a little more expensive than some options, you could find other lysine products for less that are just made for cats.

    • Great for cats and dogs
    • 100% customer satisfaction guarantee
    • Non-GMO recipes

    • Not all pet parents will need multi-pet product feature

    7. Mighty Pet MAX Lysine for Cats + NAC

    Mighty Pet MAX Lysine for Cats + NAC

    Supplement Type: Powder

    Mighty Pet MAX Lysine for Cats + NAC is a fantastic product with a lot to offer. In addition to Lysine, it also has NAC, vitamin C, and vitamin E. This product is designed to support the best health possible for felines. The NAC works to clear excess mucus from the airways while the vitamins improve immunity and eye health. With plenty of antioxidants, this product boosts overall health, making sure the respiratory system is functioning excellently.

    There are approximately 142 servings per container, so it lasts quite a while before you’ll need replacements. The powder is flavored with chicken and salmon to blend with regular foods. Your cat is sure to love the extra kick of flavor.

    The smell might be a little overwhelming for us humans, but the cats don’t seem to mind.

    • Added NAC for lung health
    • Vitamins and antioxidants added
    • Flavorful

    • Strong smell

    8. Thomas Pet Felo Lysine Supplement for Cats

    Thomas Pet Felo Lysine

    Supplement Type: Powder

    The Thomas Pet Felo Lysine is geared toward amping up antibodies and enzymes to support healthy immunity. It’s easy to serve to your feline and they probably won’t even notice a change. If your cat is having trouble, this helps them get over their hump of sickness and back to a healthy life. On top of lysine, this product contains DMG, which also improves immunity function overall. This product is tasteless, so you can mix it in with their regular meals.

    There is a disclaimer on the back stating that this product is not intended for pregnant cats. So, if you’re trying to treat a mama cat, this supplement is not the best for her safety.

    • Builds antibodies and enzymes
    • Contains immunity-boosting DMG
    • Odorless and tasteless

    • Not for pregnant cats

    9. Optixcare L-lysine Chews For Cats

    Optixcare L-lysine Chews

    Supplement Type: Chews

    The Optixcare L-lysine Chews definitely give your cat a dose to kickstart better immunity. They are specifically designed to clear up the feline herpes virus in cats and kittens. These chews are soft enough for kittens and seniors alike. Each chew is packed with poultry flavor to entice your cat’s taste buds. A single resealable bag lasts 2 months for one cat. But it can get a little expensive if you have multiple cats.

    These chews are a lot bigger than some others of their kind. Even though they are decently soft, some seniors might have an issue chewing. So, if your cat has dental issues, you might want to find another product that works better for your cat.

    • Designed to lessen symptoms of feline herpes
    • Enticing flavor
    • Resealable for freshness

    • Large size
    • Might not work for cats with dental problems


    Buyer’s Guide: Choosing the Right Lysine Supplement

    Still not sure which product is right for your feline? Take a look at our buyer’s guide for more detailed information on how to choose the best option out there.

    What Is Lysine?

    Lysine is a naturally occurring amino acid found in animal products. Since cats are obligate carnivores, they thrive on having amino acids in their diet to regulate their immunity and keep them healthy. Sometimes, when their bodies lack the ability to fight off illness, it can cause outward symptoms that affect overall wellness, respiratory health, and eye health.

    Lysine works to boost immunity and target the areas that are lacking so your cat can get back to a healthy state. Even though lysine is in almost all cat foods, it might not be enough in a meal. Adding a supplement at mealtime will help your cat regulate.

    What Other Components Pair Well with Lysine?

    In addition to lysine supplements, certain other additives can aid in the goal as well. Here are a few things that pair well with lysine products.
    • DMG: Dimethylglycine, or DMG, is an amino acid derivative that amplifies the effects of lysine.
    • NAC: N-acetyl cysteine is an antioxidant that has the ability to break up mucus. It is of great aid in many respiratory conditions.
    • Omega Fatty Acids: Lots of lysine supplements have added fatty acids to nourish and maintain a healthy body.
    • Antioxidants: several other antioxidants also work alongside lysine to build up natural immunity.

    Types of Supplements

    Cats will benefit from different lysine product consistencies depending on preference.
    • Chews: Chews are sometimes a good idea for cats who are very food-motivated. You can easily slip them a chew and they will think they’re being rewarded with a yummy treat.
    • Powder: Powder comes in both flavored and flavorless varieties. Some cats love the extra zip of flavor-based supplements, while others will reject the taste. It might be trial and error to see which your cat loves most.
    • Liquid: Liquid is usually odorless and tasteless, but it can come in flavored varieties too. These supplements are usually quite easy to measure and mix with your cat’s regular meals.

    How Lysine Helps

    Lysine can help your cats in the following areas:
    • Boosts immunity
    • Minimizes feline herpes symptoms
    • Reduces infection of the eyes
    • Clears respiratory system
    • Promotes healthy skin

    hepper-cat-paw-dividerFinal Thoughts

    We stand by our number one pick—VetriScience Laboratories Vetri Lysine Plus. It comes in soft chew form, so it works as a treat for cats of any life stage. They receive the proper dose of lysine, and the results are highly positive, boosting overall immunity and health.

    If you’re looking to save a buck or two, we also really enjoyed Duralactin Feline L-lysine Cat Supplement. It comes in a syringe in liquid form, making application a breeze. You just add the proper dose into your kitty’s daily food bowl and go!

    With any luck, our reviews led you to your newest purchase. We hope your cat’s immunity is stronger in no time.

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    Featured Image Credit: cocoparisienne, Pixabay

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