Antioxidants are the skins first line of defense, they prevent environmental damage from sun, pollution and artificial light. Environmental damage which we are exposed to daily is the cause of 90% of premature aging. SkinCeuticals antioxidant serums are formulated to effectively neutralize this daily damage. Their patented blend of antioxidants will give your skin 8x more environmental protection to improve skin health and ability to repair and reduce the appearance of aging. SkinCeuticals antioxidant serums are applied daily in the morning when you are most exposed and are locked into your skin for 24 hours.