The color that changes everything, with ME+ technology. Pure, balanced color results with natural depth and shine. ME+ reduces the risk of developing a new allergy to hair colors for people who do not have an allergic reaction to hair dyes. While the risk of developing a new allergy is reduced, the risk of an allergic reaction, which can be severe, remains. Always ask your stylist to perform an allergy test 48 hours before any coloring. ME+ is included in certain shades of the Pure Naturals, Rich Naturals, Vibrant Reds, Special Blondes, and Deep Browns from the Koleston Perfect brand.