Occlusives in cosmetics are moisturizing ingredients that form a physical barrier on the skin’s surface to prevent transepidermal water loss (TEWL), thereby locking in moisture and enhancing skin hydration. Unlike humectants, which attract water into the skin, occlusives primarily work by sealing moisture within the skin and protecting it from environmental factors that cause dryness.
Occlusives are typically oil- or wax-based substances that create an inert, protective layer on the skin. This barrier slows down the evaporation of water from the stratum corneum (the outermost skin layer), which helps maintain skin hydration and improves overall skin condition. Common occlusive agents include petrolatum, beeswax, carnauba wax, shea butter, and squalane, mineral oil, silicones such as dimethicone, lanolin, and zinc oxide.