Phthalimidoperoxycaproic Acid (PAP) A scientifically proven teeth whitening ingredient that is a safe alternative to peroxide. PAP has no negative side effects during the oxidation of tooth stains, which allows it to effectively whiten without pain or sensitivity. Full ingredients list Calcium Carbonate, Cyclodextrin, Sodium Bicarbonate, Xylitol, Phthalimidoperoxycaproic Acid (PAP), Sodium Cocoyl Isethionate, Tetrasodium Pyrophosphate, Hydroxyapatite (nano), Mica (CI77019), Mint Flavour/Aroma, PVP, Phenoxyethanol, Potassium Citrate, Sucralose, Menthol, Water/Aqua, Monosodium Citrate, Ethylhexylglycerin.