questions on l-lysine supplements?

Hello! I'm new here, and still trying to educate myself better on feline nutrition. I got my first cat (a Seal Point apple head Siamese) at 4 years old. (Which was 23 years ago) . We lost her 5 years ago, at the age of 18. Unfortunately, while we had her, I wasn't very educated on diet and nutritional requirements. I wonder if the sudden rapid decline in health she went through was at all tied to the diet of kit not kaboodle and salmon fancy feast. It's hard to say, but now that I know and have seen the benefits of high quality foods, I'm trying to do my best to give my new kitten the best care that I can!

So, to give a little background- My kitty, Nala is almost 5 months old, she's also a Siamese(applehead). I bought her from a breeder (I'm allergic to cats, but certain breeds don't bother me, siamese are one of the breeds I don't react to. Not to mention I love siamese kitties and their personalities!). About 3 weeks ago she started sneezing, so I took her to the vet. (I work at said clinic in the grooming department). She didn't have a fever or any eye discharge.they prescribed an antibiotic and lysine chews. She stopped sneezing about a week after starting the antibiotic (of course we finished out the 2 weeks as instructed). Alongside her now being picky about eating the lysine treats, I wondered if she needs to continue being supplemented? So far, it seems like it's just a good thing to keep a cat on, but I wanted some additional feedback. If she should continue being supplemented, is there a better option than the treats I was given? I'm not wild about the corn, fillers and other things that are in these chews. I've seen other brands of treats (pet naturals was one I believe? ) and powder.

If it helps, she eats wellness divine duos and healthy indulgences (grain free and non fish flavors) mainly as the wet portion of her diet (she gets a full can/pouch 2x a day, which is as much as she'll eat at a time). I leave out dry food (nature's variety instinct chicken) just to tide her over if she gets hungry since I sometimes work long days. But it's a fairly small part of her diet. She's been slightly picky with food, she doesn't like fish much and the food that's basically shredded meat (like weruva) she licks up the broth, and just picks at the meat. She's still small so maybe it's still hard for her to eat (she's just about 2lbs, though that was almost 2 weeks ago and she's grown a little since then! ) we're still trying other grain free wet foods to try to add to the rotation).

I thought perhaps if there's a good quality powder I could mix into her wet food, that might be the best option?

Sorry I wrote such a novel! Just wanted to make sure I gave enough background info

I actually use a human Lysine supplement, capsule form and break the capsule open. Mix the powder into their wet food. I usually use a smaller portion of wet food/gravy to mix in so i know they got all the supplement, then pour the rest of their food over where it was when they've finished.

The one Ive got right now is 500mg Lysine capsules by Solgar, bought it from VitaminShoppe. Considerably cheaper and on top of that, my cat hated the treats.

The most economical option I've found, and the easiest to use by far, is Now Foods brand lysine powder in a one pound bottle which I buy from Amazon.  My fella gets 1/4 teaspoon twice a day (so 1/2 teaspoon total), and the bottle lasts something like a year IIRC.  I do always get it used up before it hits the expiration date.  It's a fine enough powder that he doesn't seem to mind it much mixed into his wet food. 

GMP L-Lysine capsules.  I take out one capsule 500 mg and sprinkle some of the power in her wet food several times a day til she had had the entire capsule.

bottle of 100 five hundred mg capsules is less than $8

I figured out how many doses in a bottle now...for the 1 pound bottle of Now brand Lysine powder, there are 822 servings of 1/4 teaspoon each.  Since I give two doses a day, the 1 pound bottle lasts 411 days.  Cost via Amazon is $13.59 for the 1 pound, which (because it lasts a bit over a year) works out to $12.00 a year.  It's a pretty good deal, and it does seem to help him.

I've used Viralys L Lysine powder which I've bought on Amazon.  My cats were okay with it being mixed into wet food - there is also a paste version sold in a tube which has gotten good reviews on Amazon.