Cosmetic ingredients generally contain unsaturated components. Antioxidants are needed in the oil phase to prevent the oxidation of unsaturated components and cause rancidity; active ingredients and preservatives containing unsaturated structures need antioxidants to prevent deterioration and discoloration. Oxidation (auto-oxidation) in the air may destroy the flavor, and unpleasant odors are produced due to the reaction of oxygen with different components in the flavor.
Generally, ascorbyl palmitate and chelating agents can be added to enhance the effect of antioxidants. Antioxidants must be distributed in the water phase and the oil phase. Oil-soluble components require oil-soluble antioxidants, and water-soluble components require water-soluble antioxidants. Commonly used antioxidants include: BHA, BHT (butylated hydroxytoluene), TBHQ (tert-butyl hydroquinone), tocopherol, etc.