Different types of alcohols are used in different hair care products for specific outcomes. While most people think of alcohol as having deleterious, dehydrating effects on hair, this isn’t always the case.
Some alcohols have an intentional “drying effect” which is critical for product performance. Short-chain alcohols (like alcohol denatured, alcohol denat, isopropyl alcohol and SDA-40) help formulas like hair sprays evaporate and dry very quickly to help set and lock in styles.
Other types of alcohols (long-chain fatty alcohols, such as cetearyl alcohol) can actually provide hydrating and smoothing benefits when they are used as thickeners and emulsifiers in hair products.