If you don’t have a tattoo, you probably at least know someone who does — but what’s the chemistry behind tattoos? In this Reactions video we explore what tattoo ink is made of, why this body art is permanent (whether you like it or not) and other cool facts. For more information on tattoos, check out Claudia Aguirre's article: www.doctorclaudia.com/tattoos-and-skin-h­ealth.