HOW TO USE Apply UNITONE 4 white once a day, only at night on the areas to be treated or as directed by your dermatologist or healthcare professional. UNITONE 4 white is especially formulated for a night application. Concentrated Active Complex : slows down melanogonesis through tyrosinase inhibition Glycolic acid : decreases the corneocyte cohesion by exfoliation and reduces the preformed melanin Ascorbic Acid : diminishes the preformed melanin and has anti-radical properties.