Crest (a Proctor & Gamble brand) are the leaders in over-the-counter whitening. Crest Whitestrips were introduced in 2001. They have become the best selling teeth whitening product in the world. The Crest whitening family of products can be found at almost any retail grocery or drugstore. Since 2010, the new '3D White' ranges were introduced, offering non-slip Whitestrips. We're seeing great reviews on their 3D White line. The active ingredient in Crest Whitestrip products is hydrogen peroxide.