Acetone

Acetone is a volatile solvent used at high concentrations (often near 100% in nail polish removers) that rapidly extracts skin lipids, causing dryness, barrier disruption, stinging, and irritant contact dermatitis in susceptible users. Clinical and occupational data consistently show it to be a common irritant with repeated exposure, with heightened risk on compromised or eczematous skin. In real-world routines where hands/face may already be exposed to surfactants and actives, cumulative barrier damage makes irritation likely, warranting a high score. Safety Notes: In consumer skincare/cosmetic-adjacent products, acetone is most often encountered as a solvent/quick-drying carrier at very low levels (trace to ~1%) in some astringents, wipe/cleanser-type products, and specialty solutions where it functions mainly as a volatile solvent. At the high end, OTC consumer nail polish removers and "pure acetone" removers are commonly sold at ~60–100% acetone, with 100% (or near-neat) being widely available; these are rinse-off/evaporative-use products rather than leave-on skincare due to irritation and defatting potential.