Pet Health Solutions Felisyl Immune System Support for Cats, 3.5-oz jar

By Felisyl
Rated 4.2059 out of 5 stars
$16.44Chewy Price
$16.99Chewy Price
$15.62Autoship Price
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About This Item


  • It’s made in the USA.
  • Safe and effective for your feline friend or kitten whose condition is responsive to the essential amino acid L-Lysine, it reduces the severity and duration of feline herpes virus.
  • Made with a delicious poultry and fish flavored base, this granule supplement is easy to give your fur-iend—simply sprinkle it over food or mix in.
  • Helps keep your kitty healthy by naturally supporting his immune system so it functions normally and produces antibodies.
  • Aids in maintaining healthy tissue, supports respiratory health and may even help vision.

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Nutritional Information

Feeding Instructions


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Top IngredientsL-Lysine in a palatable base.Active Ingredients: L-Lysinehydrochloride., Inactive Ingredients: Brewer's Dried Yeast, Hydrolyzed Fish (Enzymatic)...Active Ingredients: L-Lysine Hydrochloride., Inactive Ingredients: Citric Acid, Edetate Disodium...Active Ingredients: L-Lysine Hydrochloride., Inactive Ingredients: Citric Acid, Edetate Disodium...Active Ingredients: L-Lysine Hydrochloride 500 mg., Inactive Ingredients: Arabic Gum, Brewers Yeast...
LifestageKitten, Adult, SeniorKitten, Adult, SeniorAdultKitten, Adult, SeniorKitten, Adult, Senior
Health FeatureImmune SupportImmune SupportImmune SupportEye Care, Immune Support, Respiratory CareEye Care, Immune Support, Respiratory Care
Food FormSupplementSupplementSupplementSupplementSupplement
Food FlavorChickenMolassesHerbs & Spices, Hickory

Questions & Answers

3 Customer Questions

What is the FULL ingredients list for this product? I want to know what all the fillers are...maltodextrin, magnesium oxide, etc?
Answer by ChewyApr 22, 2019
The full ingredients list for this product are as follows: L-Lysine, Natural Chicken Liver Flavor, Oat Flour, Rye Four, Soy Lecithin, Brewers Dried Yeast, Water, Arabic Gum, Glycerin, Canola Oil, Maltodextrin, Sodium Alginate, Calcium Sulfate, Citrus Pectin, Oat Meal, Sorbic Acid (preservative), Propionic Acid (preservative), and Mixed Tocopherols (preservative).

Can cats taste this?
Answer by ChewyDec 18, 2017
This has a delicious poultry and fish flavored base, to make these granules easy to give to your cat, just sprinkle over or mix in with food.

Does this work well with dry food?
Answer by ChewyNov 08, 2017
Felisyl Immune System Support for Cats can be easily mixed with wet or dry food.

ReviewsWrite a Review

Rated 4.2059 out of 5 stars
34 Ratings
Would recommend to a friend

34 Customer Reviews

Rated 5 out of 5 stars
By CarlaJakola on Jun 14, 2023

Difference is night vs day

So my 14+ yr old cat who has been treated with every medication has always been congested with draining eyes and nose. Never diagnosed with or tested for herpes. I friend recommended a lysine supplement. So I choose this brand as with 3 cats of various ages from 8 months to 14+ years a powder to sprinkle was easier than a chewable. I added this powder to all the cats’ twice daily teaspoon of canned food. WOW!! Clearer eyes. Less drainage. Her breathing is better. All around a much happier & healthier cat. My 8 yr old cat is livelier and his eye goop has stopped. The 8 month old kitten converts it directly into the zoomies.

Rated 5 out of 5 stars
By 2HappyCats on Apr 26, 2023

New Product to try

After several bouts of anitbiotics for my kitten with chronic rhinitis, I am happy to use a product that not only is non-medicine, but helps her naturally mange her condition. No drug side effects! Her sneezies have not totally gone away, but there is easily a 75% improvement. I also give this to our older feline buddy, to protect him from her germs.. 2 happy campers.

Rated 5 out of 5 stars
By lin71 on Mar 23, 2023

great price

this is a great product. My cats come running when they hear me open the jar. I have multiple rescues with multiple health issues and this is good stuff for them

Rated 5 out of 5 stars
By Tomcat on Feb 15, 2020

Felisyl blessings

Tom is my new cat, FIV positive and with respiratory herpes from his time as a stray. Felisyl powder appeals to him and already has helped diminish his sniffles as it did for my former cats.

Rated 1 out of 5 stars
By PapaJeff on May 6, 2019

Not worth the money

Wish I had saved myself ten bucks and NOT bought this. Did no good at all and smells so bad the cats hated it

Rated 5 out of 5 stars
By Bobbi on Mar 3, 2019

Just started to use this

Only gave my cat six doses so far so not sure how it will work yet.

Rated 3 out of 5 stars
By Valerie on Jan 31, 2019

No change in pets

Havent seen any great change. Better off using lysine supplement

Rated 5 out of 5 stars
By Beth on Jun 7, 2018
Top 1000 Contibutor

Worked well

Our shelter adoptee came down with a horrible case of ringworm and passed it to our other kitten. I bought this to help boost their immune systems and it certainly helped!

Rated 2 out of 5 stars
By NThomas on Mar 6, 2018

Cats didn't take to all

I really, really don't like to write negative reviews, but I also hate to waste money! I've been using Tomlyn as a food supplement for months for my indoor and outdoor kitties. The results have been amazing...(the Vetiquinol formula is good too though Tomlyn, in my view, works just as well for half the price). When ordering last month, T was out of stock so I opted for a new brand. Simply put, my cats hated it. Even my outdoor ferals that I feed would barely touch their food so that says volumes. Not sure if I simply got a bad batch? The product doesn't appear tainted and the smell seems normal. I'm gonna pass it along to another cat buddy before throwing it out. I see lots of good reviews great to hear it's working for other folks. But, as for me, I'll definitely be going back to my trusted Tomlyn brand.

Rated 5 out of 5 stars
By Annie on Feb 16, 2018

I think it's helping

I ordered 2 similar products. This is first used. Believe it could be helping. Test other when this is gone