I agree with those who are skeptical. One of our boys is from a less-than-stellar breeder and in our contract it says he MUST stay on NuVet for the first two years or his warranty is voided. I should have known better! There are much better supplements on the market if you need them. We kept Bogey on NuVet for 6 months but didn't feel he was getting anything out of them.
I'm not a nutrition expert, so I can't advise you on what are good supplements - consult your vet if you are concerned about that. But if your puppy is on a good food and in good health chances are you don't need anything.