Hydroxyapatite is a mineral form of calcium found in bone, dentin, and dental enamel, used in toothpaste around the world to help promote winning smiles. In Himalaya Botanique Whitening + Hydroxyapatite Toothpaste, plant-based enzymes from Papaya and Pineapple work hard to remove surface stains to give you whiter teeth, while Neem and Pomegranate keeps your mouth clean and sparkling.