A new study warns that over-the-counter teeth whitening products may be harmful to your teeth.
Researchers say the active ingredient in whitening strips, hydrogen peroxide, may harm the layer under the tooth enamel.
This preliminary research was presented this week at the American Society of Biochemistry and Molecular Biology Conference.
The study's lead author found that after using white strips on extracted human teeth, the teeth had less collagen and other proteins than the untreated teeth.
It's not known whether the damage is permanent.