RT Book, Section A1 Baumann, Leslie SR Print(0) ID 1174541201 T1 Occlusives T2 Cosmeceuticals and Cosmetic Ingredients YR 2015 FD 2015 PB McGraw-Hill Education PP New York, NY SN 9780071793988 LK dermatology.mhmedical.com/content.aspx?aid=1174541201 RD 2024/03/28 AB Occlusive agents are usually oily substances that coat the stratum corneum (SC) rendering an emollient effect as well as the ability to decrease transepidermal water loss (TEWL). Two of the best occlusive ingredients currently available are petrolatum and mineral oil. Petrolatum, for example, has a water vapor loss resistance 170 times that of olive oil.1 However, petrolatum and mineral oil have a greasy feeling on the skin, leaving them cosmetically undesirable, and have further lost popularity because of the greater awareness of the environmental effects of processing these products. Other synthetic agents commonly used as occlusive ingredients include paraffin, squalene, dimethicone, and propylene glycol.2 Lanolin is an example of a natural occlusive ingredient. Organic occlusive ingredients have also become increasingly popular and include argan oil, beeswax, borage seed oil, safflower oil, olive oil, jojoba oil, and tamanu oil. Occlusive ingredients seem to be most effective when placed over damp skin and are only effective while present on the skin because once removed, TEWL returns to the normal level. Occlusives are usually combined with humectant ingredients.