What it is
Alcohol Denat. is ethanol that has been denatured in accordance with excise regulations, meaning small amounts of additives have been mixed in to make it unpalatable so it cannot be consumed as a beverage. In cosmetics it functions as a solvent that dissolves ingredients which do not mix well with water or oil, and it gives an astringent, tightening sensation on skin. Because it evaporates quickly, it helps create cosmetically light, fast-absorbing, thin formulas, which is useful in non-oily sunscreens and gels. It also has antimicrobial properties.
Safety & warnings
Denatured alcohol is a debated cosmetic ingredient. It can be drying and may give skin a temporary tight feeling, and some dermatologists advise caution when it appears very high on an ingredient list, particularly for sensitive or dry skin. Others note that at the modest concentrations typical of many leave-on products, well-formulated products are generally tolerated. Those with dry, compromised, or reactive skin barriers may prefer to limit high-alcohol formulas.
Origin & sourcing
It is ethanol, typically produced by fermentation or synthetically, to which denaturants are added. The denaturants render the alcohol undrinkable but do not chemically change the ethanol itself.
History
Alcohol is denatured chiefly so that industrial and cosmetic ethanol can be exempted from the heavy taxes applied to beverage alcohol, by making it unfit to drink. Common denaturants have historically included methanol and bittering agents such as denatonium. During U.S. Prohibition, methanol was required in industrial alcohol, and poorly informed consumption of such denatured alcohol caused fatal methanol poisonings.
Questions everyone asks
What is Alcohol Denat.?
It is ethanol with additives mixed in to make it undrinkable. In skincare it works as a fast-evaporating solvent that helps create light, quick-absorbing textures.
Why is alcohol used in sunscreen?
It helps make thin, non-oily, fast-absorbing formulas and dissolves ingredients that do not mix with water or oil. This is one reason many lightweight sunscreens include it.
Is denatured alcohol bad for skin?
It can be drying and is debated. Sensitive or dry skin types may want to be cautious when it is high on the ingredient list, while many people tolerate well-formulated products that contain it.