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  6. 6-PACK Felisyl Immune System Support (360 Soft Chews)


6-PACK Felisyl Immune System Support (360 Soft Chews)

Item: 5939-6PK
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NASC Certified

This product has met all of the stringent quality and safety standards set by the NASC.

The NASC (National Animal Supplement Council) is a non-profit self regulatory group that set specific guidelines to which manufactures must strictly adhere.

This seal is meant to minimize risk by providing an easy way of communicating to consumers that a product and its manufacturer meet particular standards of quality, customer safety and service.

Those products that have the seal for NASC Quality and Safety standards have been strictly audited and were determined as meeting the following criteria:

  • Consistent manufacturing quality control
  • A system for evaluating complaints and adverse events
  • Clear and accurate labels compliant with codes and restrictions for all forms of labeling


Felisyl® is a soft chew supplement that contains the amino acid L-Lysine for use in cats and kittens for conditions responsive to L-Lysine. L-Lysine is an essential amino acid, which means that your pet's body needs it, but can't produce it, so this supplement is a perfect choice to provide that necessity.

L-Lysine HCL Immune System Support for Cats helps keep your cat healthy by supporting the immune system naturally so that it can function normally and produce antibodies. Felisyl L-Lysine HCL Immune System Support Soft Chews for Cats also helps maintain healthy tissue, supports respiratory health, and may even help with your cat's vision. The L-Lysine is in a chicken liver flavored soft chew making it easy to give to your cat.

For Use In: Cats


Guaranteed Analysis per Chew (1.5g):
Moisture (max) 11.1%
L-Lysine 250 mg

Ingredients: 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 (a preservative), propionic acid (a preservative), mixed tocopherols (a preservative).

Useful Information

Give 1-2 chews daily

WARNINGS: For animal use only.

Store in a cool dry place.

Keep out of reach of children and animals. Your pet may consider this a treat. In case of accidental overdose, contact a healthcare professional immediately.

Customer Reviews

38 Reviews
50% (19)
21% (8)
8% (3)
8% (3)
13% (5)
76% Recommend this product (29 of 38 responses)
By Pat G.
November 14, 2016
Best Purchase ever for my cat
Cleo has no problem with scarfing these down.
AND they do help her.
By Jan
Rural Hall, NC
April 12, 2016
Excellent supplement
My finicky Siamese loves the taste of these treats! Great value!
By Callie's M.
Napa, California
February 15, 2016
Good for Cat Health
Like these a lot, but only one of my cats will eat them.
By MerryMari
January 31, 2016
Lysine is good, but cat won't eat it
I think the Lysine has been helpful in reducing my cat's symptoms. However, this cat will eat ANYTHING...except this! I have to break up the pieces into little bits and stuff them ino her canned meat. She still resists, eating around the bits most of the time. I will try a different brand of Lysine and hope she will eat it. I bought a three-pack and donated two of them to a local animal shelter
By loracreklaw
August 20, 2015
Cat's decision
The first dose was well accepted, after that, he would not touch it.
By Gorgie
July 21, 2015
Felisyl Immune System Support Soft Chews)
This is an easy and tasty way to give L-lysine for all cats and especially FIV+ cats.
By cat l.
Dallas, TX
January 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.
By puzzled1
new york city
September 11, 2014
he won't eat them...
even if I break them up into tiny pieces. They're not soft enough for my old guy. I found another brand that are softer and he'll eat those.
By tcgg
April 23, 2014
It all depends
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 skiestwo
New York
March 25, 2014
Bad Purchase
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!!
By TheresaL
Cleveland, OH
March 8, 2014
Not the same
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.
By Jennajon
February 6, 2014
Great and the cat loves them!
Used as therapy treatment for my Tuxedo who was exposed to Feline Herpes as a kitten.

Works wonderfully--only wish each chew was 500 mg instead of 250mg.
By mochalatte
January 27, 2014
Helps Eye Deposits Reduce dramatically
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.
By Cindy
South Carolina
November 1, 2013
Most Economical
My vet had quoted me an outrageous price for Lysine when my cats came down with a herpes virus. This product keeps them symptom free at a fraction of the cost!
By SherylM
Miami, FL
October 15, 2013
Cat loves them
My cat wouldn't eat other Lysine treats but loves these.
By Warren
April 24, 2013
Was the formulation changed?
Last winter I purchased a three pack. My cats loved them. They were "fish" flavored, dark colored and moist.
I recently received a six pack shipment. These are chicken flavored, beige tan and harder. All three cats turn up their noses and walk away.

What happened to the formulation? I don't remember there being a choice of flavors.
By Heidibear
March 25, 2013
My "go to" Lysine chews
I have rescue cats and some have "eye" issues and benefit from Lysine. Well, there are many forms of Lysine out now, thank goodness but all of the ones my cats are supposed to like...they don't! They are so difficult!! Anyway, These chews are the most moist you can get and are easy to chew. I just widh they had more Lysine per chew, and for that I would add the 5th star! Can't have it all though huh? Thank you!
By Ely
March 19, 2013
My cats love it
I have two cats with herpes of the eye and both are happy to take 1 tab each am and pm.
By Anita
March 16, 2013
Review for 6-PACK Felisyl Immune System Support (360 Soft Chews)
This is an excellent product but the last couple of batches have been hard not soft and my cats won't eat it....I sent emails about that and they are supposed to be sending some out to replace the last ones I got...but this batch is hard too....
By Mitch
Pittsburgh, PA
February 7, 2013
Great L-Lysine Treats
The cats love them. Not real hard to get them to eat them at all.
By GreenBee
East coast of Iowa
January 16, 2013
Good for the kitties :o)
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.
By vikka's m.
upstate New York
December 14, 2012
good flavor
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 .
By Ruralex
December 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.
December 8, 2012
One of the Best purchases ever.
My Cat Lilly is doing good on this product
her sniffles and sneezing are lessoning.
It is much easier to give her the treat.
Though I must cut it in three pieces and
put it with some of her other treats.
Its much simpler to get her to eat her
immune support soft chew. That is why
I reordered 6 more packages. She is currently
doing well on 3 treats a day. She is also
much more alert and active. with her upper
resputory illmess.I would recommend this
product to other cat lovers. Try it.
By RaIrCo24
December 6, 2012
Helped my cat a lot!
My cat had sores from her feline herpes and Felisyl helped a lot to let them heal and go away. Glad I purchased this.
By Cindy
South Carolina
December 5, 2012
This is a great value. One soft chew a day and my cats are healthy and it is very cost effective.
December 2, 2012
Best purchase for my cat
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
By Kaye63
November 13, 2012
Review for Felisyl Immune System Support (60 Soft Chews)
Only a few of my cats liked the taste of this. I won't be buying it again.
By sashay
August 15, 2012
Review for Felisyl Immune System Support (60 Soft Chews)
Product smelled rancid, cats would not touch.
By Neeter
June 11, 2012
Our cats really love them...no trouble getting them down...great for when I am not feeding wet food...

Questions and Answers

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