A night moisturizer is a skincare product that is applied to the face and neck before going to bed. Its primary purpose is to hydrate, nourish, and repair the skin while you sleep. It helps to restore the skin's natural barrier function, reduces fine lines and wrinkles, and promotes healthy cell turnover. A night moisturizer usually contains ingredients that are more effective at night when your body is at rest and can focus on healing and repairing itself.