I'm a dentist and I had a patient ask me about this product that is sold on this website, so I researched the ingredients, user reviews, etc., and in my opinion the product is phony. The light is way too weak to do anything, and I believe it is included only for psychological reasons. The whitening appears to come from the zinc oxide pigment that is included in the product. I don't see anything else in it that would produce any significant whitening. This creates a nice initial impression, but in time it would wear off. The only over-the-counter tooth whitener I know of that works is Crest Whitestrips. read full review »