Masking

Ingredients with the masking function help to hide or soften the unwanted smell of raw materials in cosmetics, so that the product is perceived more pleasantly when applied and used. This is important for creams, shampoos, masks, and cleansing products, where the base ingredients, assets, or solvents may have a harsh, acidic, greasy, or "technical" flavor. Such substances primarily affect not the condition of the skin or hair directly, but the sensory properties of the product: the smell, the overall feeling of freshness and comfort from use. In European reference books on cosmetic ingredients, this function is described as masking foreign odors, but in practice it is most often associated with perfume components and aromatic molecules. (skinsort.com)

These ingredients are often added to the formula in very small amounts.: they do not change the texture noticeably, but they make the flavor of the product more neutral or pleasant. In hair products, it helps to block out the smell of surfactants, polymers and dyes, and in skin care — the smell of oils, extracts, acids or some active substances. Typical examples are Limonene and Citral: these are aromatic components that are used in cosmetics, including due to their ability to mask the odor of a composition or individual ingredients. It is important to remember that such scented substances can cause irritation or undesirable reactions in sensitive skin, so people with highly reactive skin are usually advised to read the composition especially carefully. (cosmileeurope.eu)