Preservative

These ingredients are added to cosmetics to protect the formula from bacteria, yeast and mold and keep the product safe during the shelf life and after opening. This is especially important for products with water — creams, serums, shampoos, shower gels, masks. According to the European Commission, these substances reduce the risk of microbial contamination and help the product not deteriorate during normal consumer use; the FDA also notes that an ineffective protection system increases the risk of microbial growth in cosmetics. (single-market-economy.ec.europa.eu)

Such components do not work on skin and hair as active care — their main task is not to moisturize or restore, but to ensure the stability and hygienic safety of the product. Indirectly, this is also important for comfort: if the formula is protected from germs, it retains its original properties, odor, color and texture better, and also less often causes irritation due to product spoilage. At the same time, in sensitive skin, certain substances of this group can cause individual reactions, so the FDA classifies them as possible cosmetic allergens. (single-market-economy.ec.europa.eu)

Typical examples include phenoxyethanol and methylparaben. The FDA describes parabens, including methylparaben and propylparaben, as widely used substances that help prevent the growth of harmful bacteria and mold; they are often combined to enhance protection against different microorganisms. In other words, this function is primarily needed not by the skin or hair directly, but by the cosmetic formula itself — so that the product remains functional, stable and safe from the first to the last application. (fda.gov)