I have noticed a slight improvement already with using these whitening strips. The only downside is that I have noticed is one tooth on my bottom row of teeth is very sensitive during and after the application. At first I was a bit worried but crest on the package says that it may very well happen and that it is normal. That was a relief. I will be posting some pictures soon of my teeth on my facebook and twitter. My facebook name is leah stobe my icon is of minnie mouse, my twitter is @chrissy11217 So far, so good. Excited to see how white my teeth do get.