Human remedies don't always work on cats. Lysine doesn't boost the immune system, it decreases arginine production. Some recent studies have shown that not only is it ineffective on cats, but can actually be harmful.
http://consciouscat.net/2016/01/11/...ptoms-of-feline-upper-respiratory-infections/
http://m.petmd.com/blogs/thedailyve...herpes-virus-bad-news-popular-treatment-31971
Best immune booster you can use for a cat is a GOOD probiotic since most of their immunity originates in the bowels.
http://consciouscat.net/2016/01/11/...ptoms-of-feline-upper-respiratory-infections/
http://m.petmd.com/blogs/thedailyve...herpes-virus-bad-news-popular-treatment-31971
Best immune booster you can use for a cat is a GOOD probiotic since most of their immunity originates in the bowels.