Perricone esp makes a lot of his medical credentials, until you actually look into his so called research, which is at best fanciful, down right misleading at other times, and unsupported by evidence. His long list of references rarely support what he promises, and as far as his time at medical school in Yale: he was there as a unpaid supported of students!
But if you like the stuff - and can afford it lol - then good on you, just please do not fall for the hype