yes, I give Blackberry around 250mg per day because he has some issues with runny nose and sneezing. I have been giving him lysine for about 3 weeks, and he is doing better (however I cannot say it's only lysine, i also started running humidifier in the room he sleeps, b/c it's super dry lately, and he got shot of antibiotic to help his URI few weeks ago).
I have heard though that lysine is great for cats with viral cat colds (feline herpes virus), but it takes time to see effects and the best you can do is to feed it to your cat daily, always.
I bought viralys from amazon (i got free shipping), because it smells like fish so my super picky Blackberry actually eats it with his food. But when I run out, I will likely buy just human lysine from regular store.
Anna + Josie and Blackberry