L-lysine where to get it?

Today I took Taz into the vet since it seems that he caught the uri that the kittens have. While there I let the vet know that the kittens were still sneezing after just about finishing their clavomax, have about one dose left. Along with that Leonard's eye although looking better is still slightly red around the edge. So we are going to be doing another course of antibiotics, zithromax and I will continue with Leonard's eye ointment for another week.

He also suggested trying L-lysine in case what the kittens have is the herpes virus and not just an uri. I got a 100 gm from the vet for $8
I was wondering if anyone had any suggestions for L-lysine that would be good price wise. Also is there any difference in quality to look for. I didn't want to ask at the vets since they where nice enough not to charge me for a full office visit for Taz, but charged me as a follow up visit which saved me more than half of what a normal office would be.

I'm attaching a thread that talks a little bit about what to look for and lists a couple of brands.  I know you can order it at Amazon, and can probably get it at most health food stores, just be sure to pay attention to what else is in it, per this thread:  http://www.thecatsite.com/t/250861/forms-of-l-lysine

Thank you Missgreenjeans for the link. Very good information to know when looking for lysine for my cats. I have been searching some of the other threads on lysine to get better educated with this supplement.

It's important that you give lysine twice a day.  It will only work if it stays in the blood system and since it's an amino acid, it passes out when your kitty potties.  I use the powdered NOW brand or VitaCost brand.  It comes in a 1pound container and 1/4t equals 500mg.  I usually order from Amazon.

Thank you stephanietx, will check those out on Amazon. My vet gave me directions for twice a day while showing symptoms and once a day while well. After reading threads here I will be making sure that they are getting it twice a day. Tonight the kittens are full of energy, not sure if it the lysine is making them feel better or if they are finally over the uri. They have been bouncing off the walls in only the way that kittens are able.