This is interesting because people will buy supplements that have no scientific basis for efficacy (biotin, mega-doses of Vit-C, St John's Wort) but they will deride homeopathy, which also has no scientific basis for efficacy. I'm not bashing zinc, because I don't know the science, but I am bashing homeopathy. Openly. Show me some double-blind studies. Unless the placebo effect is what you are selling, in which case, say that.

EDIT: Thanks for the info on St John's Wort! I should have picked a better example.