Using the Colgate Naturals Charcoal was a wonderful experiment for me. As I was struggling with stains on my teeth caused by tea. As i drink so much tea! Throughout the course of this trial i noticed a difference where my teeth were getting whiter and the stain’s diminishing..This is one of the many reasons that I highly recommend Colgate Naturals Charcoal; It has that whitening effect - teeth are kept clean whilst whitened.