The Colgate Optic White Oxygen Whitening Toothpaste with active oxygen bubbles gives a whiter smile within a few days of regular use. Clinically proven to whiten teeth by one shade in 3 days and 3 shades in 28 days with regular use twice a day, this toothpaste removes the stubborn and unsightly stains caused by food and drinks. As you start brushing, you can feel a warm sensation with rich foam which signals the release of millions of active oxygen bubbles, indicating that the formula in the toothpaste has started working. It removes both intrinsic and extrinsic stains by working on the deep layers of the enamel, revealing a brighter, confident smile you deserve.