Opacifying

Such ingredients make the formula less transparent and more concealable: the product looks milky, creamy or dense in color, better masks the natural shade of the base and is visually distributed more evenly. In decorative cosmetics, this helps to create a coating effect, in creams and lotions — to give the usual "opaque" appearance, and in hair products — to make emulsions and masks more saturated in appearance. According to the CosIng database, the opacifying function refers to substances that reduce the transparency of cosmetics, and the FDA and industry reference materials note that white pigments can increase opacity and reduce the translucency of the formula. (single-market-economy.ec.europa.eu)

Such components often affect the skin and hair not as active care, but as technological additives: they primarily change the appearance and texture of the product, making it visually more dense, homogeneous and "caring". One of the most typical examples is Titanium Dioxide: it is a white mineral pigment that is used to increase the opacity and visual density of the formula; additionally, it is able to reflect and scatter light, therefore it is widely used both in decorative products and in sunscreen products. Another common example is styrene—Styrene/Acrylates Copolymer or other polymer dispersions that can be used to create more cloudy, creamy-looking emulsions. It is important to understand that this function in itself does not mean a therapeutic effect on the skin or hair: its purpose is to improve the consumer properties, appearance and perception of the product. (cosmeticsinfo.org)