COSRX The Retinol 0.5 Oil 20mlHighly concentrated 0. 5% pure retinol 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. Intensive treatment for a youthful and radiant complexion! Clinical Results in 4