Propylene Glycol (PG) and water are used as solvents in hair colorants for our dyes and PG is a good choice as it helps to keep the concentration of ingredients low, reducing waste and exposure. Additionally it helps to form the crème consistency of colorants. Propylene Glycol is also a great humectant compared to other solvents like alcohol that dry out hair and skin and reduces our use of surfactants. PG has two main benefits in our new KP ME+. 1. It solubilizes the dyes to keep them equally distributed in the color crème to ensure best possible performance on hair without causing drying out of the hair. 2. It is the main ingredient in the colorant for providing a smooth crème that is easy to spread on hair and stays where it is supposed to stay.