Because of its gentleness and efficacy, dimethicone is used as an emollient component in moisturisers. Dimethicone forms a permeable barrier on the skin, preventing moisture loss and imparting a beautifully silky texture. It will also act as a formulation defoamer, reducing the greasiness that other creams left on the skin directly after application. Dimethicone is also said to shield the skin from moisture deprivation when used at higher concentrations. When mixed with other ingredients, dimethicone forms a waterproofing material for sunscreen emulsions and aids in the removal of greasiness in high-SPF preparations.

See also:
Emollient
Silicone