Cosrx The Retinol 0.5 OilIntensive treatment for a youthful and radiant complexion! No purified water or retinol derivatives. Formulated using 0. 5% stabilized, pure retinol for powerful anti aging care. Best for skin accustomed to retinol but still experiencing progressive signs of aging such as loss of elasticity and dryness. For intermediate level retinol users looking for a highly concentrated, youth booster.