I was really hopeful about these whitening strips, since my teeth are a little yellow from soda stains. These didnt really do much for me at all, they whitened a little bit but within days they were back to how they were before, even when I only drank water. These made my teeth extremely sensitive for hours after only wearing for 15 minutes. Im sure they would work better if I could use them more than once a week but the pain from the sensitivity is too much for me, especially since they havent worked too well for me. Hopefully this changes over time or maybe I should invest in sensitive toothpaste, but Ive had a better whitening experience from a dollar tree whitening gel- no joke! This is not worth the money, theyre definitely overpriced. It comes with a lot of strips but it hurts so badly.