Antiperspirant

These ingredients help reduce perspiration at the application site, so they are most often used in deodorants and underarm products, and sometimes in formulas for palms, feet, or areas with excessive sweating. According to the FDA definition, an antiperspirant is a topical agent that reduces sweat production on the treated area of the skin; for labeling "24 hours" or "all day", the product must confirm a noticeable decrease in sweating in standard tests. Unlike conventional deodorants, such substances affect not only the smell, but also the amount of moisture on the skin, which makes the skin stay dry longer, and the feeling of stickiness and wet marks on clothes decreases. (accessdata.fda.gov)

Most often, this function is provided by aluminum salts. Typical examples are Aluminum Chlorohydrate and Aluminum Chloride: the FDA classifies them as active antiperspirant ingredients in over—the-counter products, and the American Academy of Dermatology notes that it is the presence of aluminum compounds that distinguishes antiperspirant from a product that simply masks odor. In the composition, they work on the surface of the excretory ducts of sweat glands, temporarily reducing sweat output, so the main effect is related specifically to the skin condition in the application area, and not to the hair texture or decorative properties of the formula. However, in the finished product, such components also indirectly affect consumer feelings: they help the formula to give a more "dry" finish and maintain a feeling of freshness for longer. (accessdata.fda.gov)

For the consumer, this function is primarily about humidity control, not fragrance. If the product reduces odor, but does not reduce perspiration itself, it refers more to deodorizing products. Therefore, antiperspirant ingredients are especially in demand in skin care in areas where dryness, comfort and reduced friction are important. The CosIng European database also maintains an official glossary of cosmetic functions and ingredient names, which is used as a reference source for labeling in the EU. (single-market-economy.ec.europa.eu )