These whitening strips have been an all time favorite for me and my family for years. We have gone to dentist after dentist trying to get our white teeth pearly white but they always told us they could not get them whiter than they already were. The reason I purchased these in such a hurry this time was because we had family photos in two weeks and we needed everything perfect. And if the dentist couldn't do we had to turn to our favorite whitening strips. In about three days, no kidding my husband's teeth were whiter. In about five days my teenager's teeth were noticably whiter. Though, I was the last one my teeth ended up getting whiter in a week in a half. The one thing I hate is, it gets messy at times. I give this product and company a two thumbs up! This will stay in the family!