I don't use this product for teeth whitening, I use it to protect my teeth while I sleep. Using a CPAP machine has a tendency to cause dry mouth for me, which, in turn, eliminates the saliva in my mouth allowing the bad bacteria to wreak havoc on my teeth. My Dentist, Dr. Dahl recommended this product and every since I started using it, it has done wonders protecting my teeth. Two of these small tablets under my tongue while I sleep is pretty cheap insurance. I believe I've been using this for 5...