Gain 3 inches? does it work?

I would guess some of you if not most of you have seen the ad on here and probably on other porn sites, to gain 3inches in 3weeks, what i would like to know Has any-one tried it and does it work or does it do what it says on the ad.. NOT that I need it..hahaha I'm happy with what i have, just wondered if it worked look forward to read you answers.