Lipids are the skin’s fat and oil components that prevent evaporation and provide lubrication. Lipids constitute 6 – 10% of the normal stratum corneum layer of skin (the outermost layer). Lipids exist primarily in the intercellular spaces and are important because they provide a barrier that prevents a variety of substances from passing through the skin.
When incorporated into cosmetics, lipids help moisturize the skin by renewing its barrier function. Along with protecting the skin, lipids perform a moisturizing and emollient action. The way the skin’s surface looks and feels results from the intercellular matrix and the skin’s lipid content. If the skin’s lipid content (including its natural moisturizing factors) is low, skin looks dry, dehydrated, and flaky. Such skin will show more fine lines and feel rough and tight. Most importantly, the skin’s healing process will be impaired. Skin with the proper moisturization level functions better, looks softer, and feels smoother. Maintaining healthy skin requires exfoliation, massage, hydration, and sometimes moisturization. Oily skin usually does not need additional oil applied topically.