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Felisyl® Immune System Support (60 Soft Chews)

Item Number: 5939
Regular Price: $24.99Sale Price: $9.99
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Felisyl Immune System Support for Cats is a safe nutritional supplement for your cat if it has a condition that is responsive to L-lysine. L-lysine has been known to reduce the harshness and number of occurrences of herpes simplex viral infections. These infections result in fever blisters and cold sores. L-lysine is an effective ingredient of Felisyl Immune System Support for Cats.

In cats, the herpes virus is considered very contagious. What makes it so problematic is that it is a very common cause of upper respiratory infections (URIs). Symptoms of URIs include eye discharge and sinus congestion in your cat. You may also notice some squinting of the eyes and sneezing as part of the effects of an upper respiratory infection. Felisyl Immune System Support for Cats can help.

Felisyl is an easy to use nutritional supplement that kittens and cats alike seem to find tasty. It is easy to administer by simply mixing it in with their cat food.

Other benefits to Felisyl Immune System Support for Cats are that it helps promote healthy tissue, encourages respiratory health, and can even help with your catís vision. It is effective, easy to administer, and has some nice additional healthy side effects.

Administration: Approximately 1 to 2 Soft Chew L-Lysine daily.


chicken liver flavor, starch, L-lysine, water, soy lecithin, canola oil, brewer's yeast, glycerin, oat flour, barley flour, rye flour, oat meal, calcium sulfate, maltodextrin, sodium alginate, sobric acid, propionic acid (a preservative), mixed tocopherol blend (a preservative).

Guaranteed Analysis per Chew
Moisture ......... 18.6 %
L-Lysine ......... 250 mg

Give 1 - 2 chews daily.

Warnings: For animal use only.

Store in a cool dry place.

Keep out of the reach of children and animals. In case of accidental overdose, contact a health professional immediately.

Felisyl® is a manufactured in the USA in FDA and USDA approved facilities following current Good Manufacturing Practice (GMP) GUidelines.

Customer Reviews

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3.87 rating based on 23 reviews


by sashay08/15/2012

Product smelled rancid, cats would not touch.

Great product! by Kim2012 from Chicago, IL11/11/2011

I had been crushing up L-lysine pills and mixing them in my cat's food until I found Felisyl L-lysine chews. Now I don't have to worry about my cat getting the correct dosage if he doesn't eat all his food. He loves these treats, which is a big compliment coming from this picky Burmese boy!

by Kaye6311/13/2012

Only a few of my cats liked the taste of this. I won't be buying it again.

Great product by purrs from Merritt Island, Fl02/11/2014

This is a wonderful product if you have kitties with the herpes virus. The plus about this product over the other lysine chews that are available is that you feed less. Most other chews require that you feed 2 chews to get the recommended dose of 250 mg lysine, that equates to 4 chews a day required for the recommended daily dosage of lysine. With this product each chew is equivalent to 250 mg lysine and therefore you use less. The price is very good so it is overall a great product for the money. My kitties love the taste as well.

Great for feline eye infection by Gina from New Orleans, LA06/07/2012

my vet recommended lysine for Max's eye infection and it has cleared it up. He loves the treats and begs me for them each morning. Much better than the power you sprinkle on their food because you know he is getting the exact amount he needs

Value by Cindy from South Carolina12/05/2012

This is a great value. One soft chew a day and my cats are healthy and it is very cost effective.

Huge disappointment this time around. by MrsD from Erie, PA12/11/2012

I have bought these treats many times & never had a product issue with them, until my recent order came. I ordered 3 bags, & ALL 3 bags were nothing like these treats usually are! The treats were as hard as a rock, a very light tan in color; as opposed to the dark brown color they are supposed to be, & they had an odd; almost rancid odor to them. The expiration date reads 1/2014, but no way are these fresh! Kudo's to Entirely Pets for immediately offering to send me 3 replacement bags! Their customer service is as always, fantastic. I hope the new bags will be alright.

good flavor by vikka's mom from upstate New York12/14/2012

We have 4 cats on L-Lysine. The treats make it much easier to administer than pills or powder. All the cats like the the flavor of Felisyl .

It all depends by tcgg from NJ04/23/2014

They are a little tough so some cats won't like them. I have to kind of squish them a bit so the break up for my cat and even then, she is not thrilled with them.

by from 06/04/2012

After trying several brands of Lysine treats that not all of my kitties would eat, I decided to try this brand & I'm glad I did.

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Great for Cats Missing Teeth by LindaD303 from Northglenn, CO04/03/2012

My Siamese cat is missing all of his chewing teeth and these chews are soft enough for him to eat. He's a very picky eater and likes the flavor of these chews. I have noticed that he has less eye discharge with the lysine supplement in these.

UPDATE to previous review on Felisyl by MrsD. from PA12/21/2012

The replacement shipment that EP's was kind enough to send to me, was just as bad as the original order I bought of these. I did notice the lot numbers & expiration date, were the same on the replacements as they are on my orginal order, making me believe this might be an inferior batch from the company who makes these. Both shipments of Felisyl I received, were very light tan in color & as hard as a rock. Nothing at all like the dark brown soft treat they used to be. I hope the compnay who makes these treats doesn't plan to make them the way I received them, because I will not be buying them anymore if they do.

by from 01/08/2013

Wont purchase again. by MrsD from PA01/09/2013

The last 2 shipments of Felisyl were nothing at all like the product I used to get. EP's was kind enough to send me a replacement order to see if I just got a defective batch, but the new batch was just as bad. The treats used to be a very dark brown & very soft, but the 2 batches I received were a light tan & hard as a rock, & smelled nothing like they once did. I was not going to feed my kitties these Lysine treats; when they looked & smelled totally different from how they once did. I dont know if the manufacturer of these treats changed the formulation or not, but I will never buy them again. Kudo's to EP's for their excellent & prompt customer service in resolving this issue.

Great L-Lysine Treats by Mitch from Pittsburgh, PA02/07/2013

The cats love them. Not real hard to get them to eat them at all.

Best Purchase Ever by Angel01/21/2013

Great product. Our 4 cats love these. They keep the symptoms of the herpes virus away.

Not the same by TheresaL from Cleveland, OH03/08/2014

I usually buy Vetri-Lycine for my cats; 250mg l-lycine chewy treats that I give to the ones who need it (four or five) and they love it. We make it a fetching game. I thought it wouldn't make a difference buying this brand instead - Felisyl - and they completely rejected it. They would chew it and spit it out. I was left with gooey lumps all over the kitchen floor. I unfortunately had ordered multiple bags but rather than go through the hassle of trying to return and get a refund, I just threw them out.

Felisyl by cat lady from Dallas, TX01/21/2015

The cats are not eating this treat and I have 11 cats, none of them liked it. I ended up giving them L-Lysine smashed and mixed with their food.

Helps Eye Deposits Reduce dramatically by mochalatte01/27/2014

In a few weeks, with twice day dosing, she ate it with her dry food but I HAD TO DICE IT UP BECAUSE IT IS TOO HARD FOR HER TO CHEW BUT she ate it if cut up and mixed with her dry food. She is very finicky and ate it. Her eye issue and breathing improved the first week by 50% and the second week by 90%. Once a day she may have some issue and I give her one a day now and one day she had no eye deposit in her tear duct and it has only been two weeks! The product needs more moisture though because even sealing the bag it does dry out to become very hard when the bag still has 1/3 of the contents left at 2x a day.

Bad Purchase by skiestwo from New York03/25/2014

I have two cats, one I call the goat because he eats anything including things like duct tape, paper and who knows what else. Well neither cat will touch this stuff. I gave it to them and they didn't even think about it, just sniffed it and walked away. My neighbor has three cats and we tried it on them and the same result. Waste of money!!

cats like them by gloworm from Alabama01/20/2013

My cats like this treat and it is an easy way for them to get their medicine

Best purchase for my cat by BABS from FL12/02/2012

My cat Lilly has upper resp. disease. She is responding well to Felisyl Immune System Support soft chews. Sneezing and sniffles has decreased. Have already purchased 6 more packages. I would recommend this product.

Felisyl by Ruralex12/13/2012

I purchased these as back up in case I run out of the Enisyl-F paste. The kitties love them so I think it's a good alternative to the paste. Only problem was some of them were broken up so it affects the proper dosage.

Cat loves them by SherylM from Miami, FL10/15/2013

My cat wouldn't eat other Lysine treats but loves these.

My cats love them by SnapLilly06/10/2012

I usually get the Enisyl-F Lysine treats, but they were out this time. I decided to try the Felisyl. You only need 1 or two and both my cats love them. They are about the same price but you can give them less. They are more like a soft treat the others are a little harder. No complaints from the cats and they will not eat anything they do not like.

Good for the kitties :o) by GreenBee from East coast of Iowa01/16/2013

Several years ago we adopted two kittens who had upper respitory issues. Our vet suggested trying L-Lysine. It helped get them healthy (I believe) and I really think by keeping them on the L-Lysine it helps keep them healthy.

Great product! by Joan from St. Joe, Michigan04/22/2013

Felisyl (l-lysine) works wonders for kittens vulnerable to upper respiratory infections and cats with eye issues. I give daily as a treat and it keeps them from visiting the vet.


Questions and Answers

3-PACK Felisyl® Immune System Support (10.5 oz)3-pk Felisyl Immune
Reg price: $47.58
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6-PACK Felisyl® Immune System Support (21 oz)6-PACK Felisyl® Immune System Support (21 oz)
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3-PACK Felisyl® Immune System Support (180 Soft Chews)3-PACK Felisyl® Immune System Support (180 Soft Chews)
Reg price: $50.99
Sale price: $27.99
6-PACK Felisyl® Immune System Support (360 Soft Chews)6-PACK Felisyl® Immune System Support (360 Soft Chews)
Reg price: $97.99
Sale price: $53.99

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