I first tried bleaching at the dentist. Was okay, probably whitened about 5 shades and cost around $400. As a touch up, I thought I'd try Natural White Pro. It said to use for 14 days...within 4 my teeth were sparkling white, much whiter than the "best they could achieve" at the dentist!!! I absolutely recommend this product. The only problem is that it can irritate your gums, if so try only using it once a day. You'll still get a fabulous smile. I use it about once a month now only 2-3 times to keep up the brightness. Can't recommend it enough!