Our current vet suggested my little guy take Denosyl because he had a particular liver value that had been out of whack for a couple of years and was getting worse with each testing. At the time I am writing this review, Riley has been on this supplement for about 3 years and has not seen any significantly bad change in that liver value since. So yes! This supplement does work! If your vet suggests it, I urge you to seriously think about giving it to your pet. It may be just the thing your pet needs to help him live a healthier, happier and, most importantly, longer life with you.