Day Preventive Treatment helps slow signs of aging by preventing damage, boosting collagen, and brightening skin tone. Formulated with Tetrahexyldecyl Ascorbate (THD) an effective and well tolerated form of Vitamin C and two other powerful antioxidants that work together to protect your skin before, during, and after exposure to UV radiation, pollution, blue light, and other sources of skin-aging free radicals. Every ingredient is nontoxic, vegan, and biodegradable.