Moisturisers or moisturizers (see spelling ifferences) 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). 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 thrown together at home using common pharmacy ingredients.