Review (5/5): More than just a teeth whitener
This product was recommended to me by my dentist for natural teeth whitening. I use it weekly, since it also has antioxidant properties, in addition to thorough cleaning. She recommended that I leave it in my mouth for up to 20 minutes, since the activated charcoal is an added benefit.
It is very messy, but it does the job. I use a small amount on a damp toothbrush, and carefully brush and spit into the sink so as not to splash anymore than needed. I would not recommend use in a shower, unless you want to wash down the walls. :-)
After use, I am compelled to use dental floss, since every spot not caught by the toothbrush shows a telltale black. It also shows any spots on the tongue that need additional brushing.
It does a great job removing surface stains, but I have not found it to whiten my teeth more than a shade or two.