Ingredient

Alcohol Denat.

Denatured Alcohol SD Alcohol Ethanol Denat.

What it is

Ethanol rendered undrinkable with a denaturing additive; used in cosmetics as a fast-evaporating solvent/carrier and mild antimicrobial aid rather than as a leave-on toner-style solvent.

How it works

Dissolves other ingredients and pigments, then evaporates quickly after application, helping a mascara film set fast; also contributes mild antimicrobial and astringent action.

What it does

Solvent Viscosity controlling

Concerns to know

Drying alcohol

A volatile alcohol that can compromise the skin barrier and dry the skin at high concentrations.
Caution for infants

Better avoided on infant skin, which is thinner and more permeable; prefer fragrance-free, minimal formulas for babies.

Evidence at a glance

Worth knowing

Reflects its most significant known concern.

Why this rating

Drying alcohol

Denatured ethanol is a recognized defatting/drying agent that can strip lipids from skin with regular exposure, particularly relevant on the thin eye-area skin a mascara contacts; CIR safety reviews of SD alcohol note irritation potential depends on concentration and formula position, so it is flagged even though mascara typically uses it as a minor fast-dry aid rather than a solvent-heavy base.
Caution for infants

Better avoided on infant skin, which is thinner and more permeable; prefer fragrance-free, minimal formulas for babies.