Can teeth whitening damage my teeth? Are over-the-counter teeth whiteners safe and effective?Not all whiteners are safe. Since there are no DEA restrictions on this over-the-counter category, I would use caution when using these products. The key ingredient is carbamide peroxide. Some of the over-the-counter products are gimmicky, diluted or very acidic. Although there aren’t any current articles that suggest long term effects on an individual’s enamel, I would recommend consulting a dentist for the most safe and effective teeth whitening solution.