The strongest teeth whitening products available for purchase typically contain higher concentrations of hydrogen peroxide or carbamide peroxide, which are the active ingredients responsible for bleaching teeth. These products are often found in professional-grade whitening kits or treatments available from dentists. Over-the-counter options with higher concentrations of these bleaching agents, such as whitening strips or gels, can also provide significant whitening results. However, it’s essential to use these products cautiously and follow the instructions carefully to avoid potential side effects such as tooth sensitivity or gum irritation. Additionally, consulting with a dentist before starting any intensive whitening treatment is advisable to ensure it’s safe and suitable for your dental health.