Skin conditioning - occlusive

These ingredients help the skin lose less moisture: they form a thin protective film on the surface, which reduces transepidermal water loss and thereby maintains softness, smoothness and a feeling of comfort. This makes the skin look less dry, reduces the feeling of tightness and roughness, and the damaged or weakened skin barrier is restored faster. That is why such components are especially common in creams for dry, sensitive and irritated skin, as well as lip balms and hand protectors. The effect of this group is well described in the dermatological literature: occlusive substances act as a barrier, reducing the evaporation of water from the skin surface. (ncbi.nlm.nih.gov)

In the formulation of cosmetics, they affect not only the care properties, but also the texture of the product. Formulas with such components usually seem more dense, nutritious, gliding and "protective" in feeling than light gels or fluids. On hair, the pronounced effect of this function is less common, but in some products, the film may slightly smooth the surface of the hair and reduce the feeling of dryness. Typical examples include Petrolatum and Mineral Oil: petroleum jelly is considered one of the most effective occlusive components and is able to significantly reduce water loss, while mineral oil also creates a protective layer and helps retain moisture in the stratum corneum. (ncbi.nlm.nih.gov)

It is important to understand that such ingredients do not "moisturize" the skin with water directly, but rather retain existing moisture. Therefore, they are often combined with moisturizers, such as glycerin, to both attract water and retain it in the skin. They are most useful for dryness, cold weather, frequent hand washing and impaired barrier function, when the skin especially needs additional protection from moisture evaporation. (ncbi.nlm.nih.gov)