Whiten your teeth in as little as 15 minutes at home with this professional strength formula. This gel is formulated to store in the refrigerator for touch ups for up to 2 1/2 years... It is optimized to eliminate and/or minimize sensitivity. Be 4-8 Shades Whiter in 20 Days or Less, GUARANTEED. Only 30 minutes or less per application. We also include the Dentist recommended remineralizing gels used after bleaching to strengthen teeth and more importantly, to help teeth regain mineral balance in less than 3 hours. Without the remineralizing gel, teeth can take up to 5 days to rebalance.