Hydration is essential to maintain the firmness and smoothness of the skin. Moisturizers help hydrate the skin by two main mechanisms. Depending on the active ingredients, moisturizers can either attract water from surrounding areas (deeper tissue or external environment) to the surface of the skin or prevent water loss from the skin to the environment by providing an impermeable seal. Some moisturizers may even contain synthetic ceramides, an oily substance normally produced by the skin itself, as an added ingredient to help with moisturization.
Different areas of the body have different hydration requirements. Thinner skin (ie. eyes, neck) or skin that is more prone to drying (ie. hands) require a heavier moisturizer. The oily T-zone area of the face, may require a lighter and noncomedogenic (non pore-blocking) moisturizer. Hence, there are specialized moisturizing creams formulated for different parts of the body.
Moisturizers should be used twice a day or more if needed. Remember, maintaining a consistent level of moisture in the skin will help maintain radiance of the complexion as well as keep wrinkles at bay years down the line!