@model_dea: I used seven of the whitening strips over the course of a week and a half. It wasnt a drastic whitening difference IMO but my staining wasnt AWFUL either and i could just not be seeing it (yall tell me your opinion in the comments) Only spot that didnt get whiter and i expected it not was right at the root of my teeth (i have slightly receeded gums, so from my understanding that will always have the slightest yellow shading to it) As far as sensitivity, it was awesome for sensitive teeth. I never got irritated and my oral health does feel better. I would keep using these for sure. Let me know if you try it! BIG NOTE: the gel sticks. You gotta gently brush and floss afterwards to get it out. Its not tough to do, but def make sure you have time for that. #amazonfinds #teethwhitening @Erica Ray