Dry skin is a problem for almost all human beings. Moisturizers help to lock in moisture and keep skin smooth, vibrant, and healthy.
Moisturizers soften and moisturize the skin. They can be formulated as creams, oils, lotions, even sprays. They can also, on a short-term basis, improve the texture and tone of skin. Moisturizers are emulsions of water and various oils, and are usually enhanced with humectants (a substance that helps the skin retain moisture), sunscreen, soothing agents, occlusives (an additive that slow the evaporation of water from the skin), vitamins, and other types of ingredients. Different formulations exist for different areas of the skin-face, hands, arms and legs-and for various skin types.
How it works: Humectants are moisturizing agents which attract and hold onto water molecules. Glycerol, for example, a humectant common in moisturizers, has three hydroxyl groups which attract water up from lower layers of the dermis and keep it from evaporating off of the skin. Occlusive agents, like petrolatum, create a thin film over the skin that prevents water from evaporating off. Humectants and occlusives are usually used in combination for maximum hydration.
Active ingredients: Humectants (glycerol, sorbitol, urea) attract and hold water in the epidermis.
Buy: At a pharmacy or department store. Generic moisturizers cost as little as $2 an ounce; luxury brands go for as much as $50 (and upwards!) an ounce.
New developments: The most recent developments in moisturizers have had to do with replacing synthetic chemicals-some of which are suspected to be harmful -with naturally-derived ingredients, such as shea butter and cocoa butter. Mineral oil, for example, is an occlusive, but can build up under the skin and prevent the absorption of vitamins and minerals.