This product has done a good job whitening my teeth, I am noticing a difference after two weeks of use! I drink a lot of tea, so I will always be fighting the tea stains, but the Smiletime whitening pen is so easy and practical to use, it is now a part of my teeth-brushing routine before bed. Brush teeth, quickly brush product on teeth, and go to bed. Noticeably whiter teeth will be part of my routine from now on. I love this product!