The greasiness of occlusive agents such as petrolatum and lanolin can limit their clinical usefulness due to lack of cosmetic elegance (2-5). For example, odor and potential allergenicity may limit the use of lanolin. Although mineral oil demonstrates less capability to reduce TEWL as compared to some other occlusive agents, it is a popular formulation component due to its favorable texture and easy spreadability (5). Silicone derivatives are also popular formulation ingredients as they may serve both occlusive and emollient functions, do not impart a greasy feel to the skin, exhibit a barrier protectant effect that is often incorporated into “hand creams,” and are used in combination with petrolatum to achieve greater cosmetic acceptability by reducing the greasiness of the overall product texture (2,5).
Most effective formulations which enhance skin moisturization include humectant agents, such as glycerin, hyaluronic acid, urea, ammonium lactate, and panthenol, which serve to attract water from the dermis into the epidermis, with some humectants also imparting emolliency (1-5). In order to prevent exacerbation of TEWL, a humectant agent
should always be combined with an occlusive ingredient. For example, skin application of glycerin alone without an accompanying occlusive agent results in a significant increase in TEWL (29%) (2,3,5). As referred to above, although emollients may vary in their inherent moisturization and barrier maintenance properties, the elegant characteristics they impart to the overall product may be appreciated by the user after product application and often relate directly to consumer product preference (5).