Within the past few months I've started drinking 1 cup of coffee every afternoon (Nescafe Classico instant made w/skim milk - yummy!). I was surprised how much yellower my teeth became just drinking 1 cup a day. I don't really like using the white strips, except before special occasions. Saw this in the store & figured I'd try it. I saw a difference within 2 days. Don't think this will make my teeth super white but they are definately less yellow. I would reccomend this.