I've seen this product a few times before, and was always curious. I've used GOsmile Ampules before and loved them! The Sales Associate at Nordstroms saw me eying this and explained how to use it, how it works, and told me she used it. She has the most amazingly white teeth, so I decided to give it a go. After reading through all the directions I've just finished my 3 10-minutes treatments and WOW! My teeth are about 5-6 shades lighter! I don't drink or smoke, but I enjoy drinking the occasional soda, and drinks lots and lots of tea. I also took tetracycline as a teen and this has added some brown to my teeth. This made them SO WHITE and pretty! It even got rid of tea stains around my gums that flossing hasn't helped at all. So far my teeth aren't sensitive either, which is a huge deal for me. I'd go ahead and give it a try! If you decide you don't like it you can always return it!