Why use hair masks? Depending on the active ingredients used, hair masks will moisturize, nourish or repair your hair. If it contains purifying agents, it also allows to cleanse the scalp, to treat greasy roots and/or to eliminate dandruff. Castor oil, argan oil, mustard oil or coconut oil are among the vegetable oils to be favored for silky hair. Used regularly, they nourish your hair in depth and make your hair softer and shinier.