Surfactant/cleansing

SURFACTANT/cleansing ingredients help the water mix with sebum, makeup residue, and other contaminants to make them easier to wash off skin or hair. Due to this, they are responsible for cleanliness after washing, shampooing or showering, and also affect the sensations of the product: how well it foams, how it is distributed and whether it leaves behind a feeling of "creaking" or, conversely, a milder cleansing. In cosmetics, such substances are especially important for gels, shampoos, foams, and makeup removers; the cleansing products themselves are directly related to products designed to cleanse the body and hair. (fda.gov)

By their action, such components are not the same: some cleanse more actively and give abundant foam, others work more gently and are more often used in formulas for sensitive skin, dry hair or baby products. If the surfactant system is too rigid, the skin may feel drier and tighter, so manufacturers often combine several cleansing agents to balance effectiveness and comfort. In addition to removing impurities, these ingredients help to evenly distribute the formula over the surface of the skin and hair, as well as maintain a stable texture of the product. (fda.gov)

Typical examples are Sodium Laureth Sulfate, which is often used in shampoos and gels for pronounced cleansing and good foam, and Cocamidopropyl Betaine, a milder surfactant that is added for delicacy and sensory enhancement. The specific sensation after application depends not only on one ingredient, but also on the entire formula, the concentration of surfactants and the presence of emollient additives. Sources: The CosIng Cosmetic Ingredients Database of the European Commission and the FDA materials on cosmetic cleansers. (ec.europa.eu )