Moisturizer are complex mixtures of chemical agents specially designed to make the external layers of the skin (epidermis) softer and more pliable, by increasing its hydration (water content) by reducing evaporation. Naturally occurring skin lipids and sterols as well as artificial or natural oils, humectants, emollients, lubricants, etc. may be part of the composition of commercial skin moisturizers. They usually are available as commercial products for cosmetic and therapeutic uses, but can also be made at home using common pharmacy ingredients.

Moisturizers prevent and treat dry skin, protect sensitive skin, improve skin tone and texture, and mask imperfections.