The shots worked pretty good for Taz. I'd have to say over all it did take a good 3 maybe 4 months for him to be back to "normal". We had to take him back a few times to get another shot. They lasted about 30 days at a time. But then he hasn't had to have another since. I also started feeding him Cat Chow for indoor cats as well as canned food, a couple different brands. But now I have to have him on a special diet for his kidneys.