Vetoquinol Viralys Powder Immune Supplement for Cats

By Vetoquinol
Rated 4.646 out of 5 stars
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About This Item

  • A highly palatable L-Lysine HCI Nutritional oral powder for cats that may be sprinkled over dry food or mixed with a small amount of canned food
  • For cats and kittens as a nutritional supplement for conditions responsive to Lysine such as upper respiratory problems or feline herpes.
  • This powder will also help reduce inflammation of the eyes, conjunctivitis (eye discharge), squinting sneezing, sinus congestion, and so much more.
  • This L-Lysine supplement is specifically developed for cats and kittens and contains naturally occurring amino acids
  • Made in the USA and manufactured according to rigorous pharmaceutical standards, L-Lysine powder can be safely administered with no known side effects for as long as required
Play Video: Learn More About Vetoquinol From Our Team of Experts
Learn More About Vetoquinol From Our Team of Experts

Trusted Immune System Support

Adding L-lysine as a supplement to your cat's diet is an easy way to help support her long-term health. As a market leader with a wide range of L-lysine products, Vetoquinol puts this active ingredient in tasty chews and bite-size morsels, plus paste, gel and powder form so you can find the best way to offer it to your kitty. These supplements are specifically designed for felines to support the immune system, and maintain respiratory an

Seal of Quality

Out of thousands of animal supplement companies, only a hundred are audited NASC members, including Vetoquinol. That means they've undergone a comprehensive quality audit to earn the NASC Quality Seal. Displaying this seal on their products means that you can rest assured that they are committed to following the highest current standards of quality in the industry.

Enisyl-F & Viralys Products

Specially formulated Enisyl-F was the first lysine-based nutritional supplement developed for veterinary use for kitties. Supplementing with L-lysine is helpful for managing the symptoms of upper respiratory infections in kittens and cats that were strays, and those in shelters.


Veterinarian formulated to deliver just the right dose in a treat with cheese, chicken, liver and hickory smoke flavors.


Tiny mouthfuls of L-lysine disguised as a delicious snack with savory chicken fat and chicken liver.

Oral Paste

Highly palatable paste that can be given by mouth, mixed with food, or even applied to paws for your cat to lick off.

Oral Powder

Delivers L-lysine HCl in a powder with fish and poultry liver flavors that cats crave—just sprinkle it on top of food.

Oral Gel

Cats only need a small amount of this extremely palatable gel to get the benefits of L-lysine HCl.

About Vetoquinol

Vetoquinol is a family-owned company devoted exclusively to finding innovative solutions for animal health issues. They've shown more than 80 years of dedication, researching everything from oral hygiene to urinary and kidney health to create products that are effective and safe for the pets you love and care about. Founded in 1933 with an expertise in pet pain management and veterinary resources, Vetoquinol has gained the continued trust of pet parents and vets worldwide.
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Top IngredientsActive Ingredients per 1 scoop (0.52 grams): L-Lysine Hydrochloride ..... 500 mg Inactive Ingredients: Brewer's Dried Yeast, Hydrolyzed Fish (enzymatic), Hydrolyzed Poultry Liver (enzymatic)...Active Ingredients: (Per Included Scoop) L-Lysinehydrochloride 500 mg., Inactive Ingredients: Brewer's Dried Yeast, Hydrolyzed Fish (Enzymatic)...Active: L-Lysine Hydrochloride: 250mg per 1.25 mL., Inactive: Citric Acid, Edetate Disodium...Active Ingredients: L-Lysine, N, N-Dimethylglycine HCl (D mg)....Dried Brewers Yeast (grain & soy free); Catnip (Leaf); Chicken Liver (hydrolysate); Fish Oil (Salmon); L-Lysine Mono HCl; Mixed Tocopherols or Natural Tocopherols (Natural Preservative); Quercetin Dihydrate; Rosemary Leaf Extract....
LifestageAdult, Kitten, SeniorAdult, Senior, KittenAdult, Kitten, SeniorAdult, Senior, KittenAdult, Kitten, Senior
Food Flavor--, ChickenChickenMolassesChicken, Liver, Poultry, MeatChicken, Tuna
Health FeatureImmune Support, Respiratory Care, Eye CareImmune SupportImmune Support, Respiratory Care, Eye CareImmune SupportImmune Support, Eye Care, Respiratory Care, Allergy Relief
Food FormSupplementSupplementSupplementSupplementPowder
Special DietNatural, No Corn No Wheat No Soy, Non-GMO

Questions & Answers

41 Customer Questions

What kitchen-friendly unit does a gram scoop convert to? For example, is "one rounded scoop" something like a teaspoon? Tablespoon?
Answer by ChewyMay 30, 2018
One rounded scoop is equivalent to one teaspoon.

I have the gel and chews but they have sucrolose sweetners. Two of my kitties are diabetic one diabetic and hypothyroid. Your powder has lysine only listed on ingredients. Is this all that is in powdered form?
Answer by ChewyNov 30, 2017
This product contains L-Lysine Hydrochloride as an active ingredient. The inactive ingredients are Brewer's Dried Yeast, Hydrolyzed Fish (enzymatic), Hydrolyzed Poultry Liver (enzymatic), Mixed Tocopherols (a preservative), Sodium Acid Pyrophosphate, and Sodium Sulfate.

Can this product help prevent urinary tract infections and Crystals like the powder with the cranberry? Thank you
Answer by ChewySep 22, 2017
The cranberry phenols help prevent bacteria from adhering to the bladder walls and acts on as preventative for UT infections so it doesn't work for crystals since it has no effect on urine pH. Also, L-lysine has no effect on urinary tract infections. However, this product is used more managing herpes virus in cats.

Is there any difference between L-Lysine and L-Lysine HCL. We have been giving our cat L-Lysince, but I see that Chewy only has L-Lysine HCL.
Answer by ChewyJul 29, 2018
The HCl denotes that the lysine is present as the hydrochloride salt. Salts changes the properties of the lysine, making it more soluble.

ReviewsWrite a Review

Rated 4.646 out of 5 stars
531 Reviews
Would recommend to a friend

531 Customer Reviews

Rated 5 out of 5 stars
By Jenn on Nov 23, 2022

it works for leaky eyes!

I got this for my rescue cat who’s been having an eye and respiratory infection for months. She’s difficult to handle so it was nearly impossible to get prescribed eye drops or other antibiotics in without it being a traumatic experience for both of us. This powder when given a scoop consistently has really helped. Her eyes aren’t completely clear yet but she is no longer squinting! It’s easy to mix in with a bit of wet food and water and they don’t mind the taste. I think they like the flavor. I noticed there are less runny noses and droplets around the house as well!

Rated 5 out of 5 stars
By CatMom1111 on Nov 15, 2022

Works great at clearing cold like symptoms

I love this stuff- I gave it to my cat who was sneezing and having upper respiratory issues and it cleared up in just a few days! I am going to make sure to keep some on hand- it works just as well as expensive medicine you get from the vet, and my cat takes it with no problem. The powder comes with a tiny scoop in it- and you just sprinkle it on wet or dry food. I like that it's so easy to use. (Note- sometimes the scoop gets buried in the container, make sure to look for it as it is a good bit smaller than any scoop I've seen with anything else). The powder also lasts for awhile because it doesn't take much to give your cat an effective dose. Definitely worth the money.

Rated 4 out of 5 stars
By Katelyn on Nov 2, 2022

Great Product - High Price

I bought this product for my cat because he will not eat the treat version that our veterinarian provided us with. This powder is a life saver because he doesn’t have any problems with it. I sprinkle it on top of his food and he eats it up like a champ. I am thankful for this product because my little fur baby isn’t sneezing 10 times in a row anymore and his eyes aren’t leaking as much, but it definitely isn’t the cheapest product in the world. I get it - you get what you pay for and with a fast working, high quality product like this I’m sure that no other products even compare on the market. Overall, it is great and I will definitely be purchasing again.

Rated 5 out of 5 stars
By Kris on Nov 12, 2022

Great preventative!

My cat was visiting the vet almost monthly for ear or eye issues. We saw a new vet who recommended this. It works great. We haven't been back to the vet in months! My 3 cats get this twice a day and a jar lasts about a month. Much better than $100 a month in vet visits.

Rated 5 out of 5 stars
By Kittymama4 on Nov 1, 2022

So far so good!

This was suggested by my vet, my cat has feline herpes and has constant upper respiratory issues of sneezing and coughing. Vet said this will help keep virus at bay and help strengthen her immune system. We mix recommended dosage into her wet food and she eats it right up. The powder smells fishy too which I guess is a good thing. So far so good!

Rated 5 out of 5 stars
By wmagics on Oct 9, 2022

On our second tub

I genuinely think this helps my cat with respiratory issues. We're on our second tub, which is saying something because if he detects anything strange in his food, he will flee and refuse to eat even when hungry. I can add this to any food and he will lap it up, even if the food isn't to his liking on its own. I love that I can get this so easily through Chewy for my little buddy.

Rated 5 out of 5 stars
By RozB on Sep 22, 2022

Always hav on hand..

I always have this product on hand. We live on a farm and are frequently visited by strays and half feral cats with respiratory problems. This is my go-to when they visit. If they stay long enough, I do get them in for spay/neuter and shots but often they don't. I think it helps.

Rated 5 out of 5 stars
By Joseph on Nov 7, 2022

Great product

The product arrived quickly and is helping my cat. Taste is an issue mixing it with his wet food but he still eats most of the treated meal.

Rated 5 out of 5 stars
By Trinity on Oct 25, 2022

Viralys powder

I was recommended this product by my vet, to help boost my cats immune system. It seems to work well, and they have no problem eating it. I add it to wet food.

Rated 5 out of 5 stars
By Sneezing on Nov 17, 2022

So very helpful

This is a great product, we have all four of our cats on it. It helps them not get those upper respiratory infections.