Denatured Alcohol (Alcohol Denat.)
Also known as: SD Alcohol, Ethanol, Alcohol Denat.
The controversial solvent that's fine in SPF, useful in toners, and drying in leave-on treatments โ context matters.
What It Does
Deep Dive
Not all alcohols are equal. Fatty alcohols (cetyl, stearyl, cetearyl) are emollient and non-drying. Denatured alcohol (ethanol/SD alcohol) is a fast-evaporating solvent that helps absorption and quick-drying finish โ perfect for SPF and some oil-control toners, drying and irritating in leave-on serums for dry/sensitive skin. Context is everything: high on INCI of a Japanese sunscreen is a formulation benefit; high on a moisturizer for dry skin is a red flag.