Propellant

Such ingredients are needed primarily in aerosol cosmetics: they create pressure in the cylinder and help the product to escape in the form of a spray, foam or a fine cloud. Due to this, the product is distributed more evenly, covers the skin or hair faster and forms the desired texture of the feed — from a light haze to a dense foam. These substances usually have a minimal effect on the condition of the skin or hair, because their main task is not care, but technological: to ensure stable spraying and ease of use. In the labeling of aerosol products, such components are indicated separately, and for hydrocarbon propellants, the FDA requires special warnings about proper and safe use. (fda.gov)

Typical examples include butane and isobutane; propane is also often used. It is these substances that are often found in deodorants, dry shampoos, hair sprays and shaving foams, because they help to quickly displace the composition from the package and get an even spray. In the European CosIng database, the propellant function is highlighted as a separate cosmetic ingredient role, meaning it is a recognized technological function rather than a marketing designation. At the same time, safety is especially important for aerosol forms: for example, the FDA specifically bans certain propellants and restricts certain substances in aerosol cosmetics if they may be dangerous to health. (ec.europa.eu )