Kojyl Methylenedioxycinnamate

Kojyl Methylenedioxycinnamate is a kojic-acid-derived skin-brightening agent used at low concentrations, but kojic acid derivatives have a clinically documented tendency to cause irritant contact dermatitis and occasional allergic reactions in sensitive or eczematous skin. Because robust independent patch-test data on this specific derivative is limited and it is typically used in leave-on formulas (increasing exposure time), I score it as moderate to reflect meaningful irritation risk and the need for patch testing in reactive patients. Safety Notes: Kojyl Methylenedioxycinnamate is a kojic-acid derivative used as a leave-on skin-brightening active; in commercial serums/creams it commonly appears at low supportive levels around 0.1–0.5% as part of multi-ingredient brightening systems. Higher-strength OTC niche “spot corrector” and intensive discoloration products have been marketed up to ~2–3% to claim stronger tone-evening performance while staying within typical solubility/sensory constraints for leave-on emulsions and anhydrous systems. It is uncommon in rinse-off at meaningful levels due to limited contact time, so the observed market range is primarily from leave-on products.