The secret to Whitening Source DermDefinition UV Lotion (SPF50) lies in its five â??active" systems which work together to deliver five benefits â?" spot prevention tone improvement prevention of sebum oxidation long-lasting penetration of active and long-lasting hydration of up to eight hours â?" alleviating issues caused by external environmental factors. Whitening Source DermDefinition UV Lotion (SPF50) contains thio-amino acid an anti-oxidant. The anti-oxidant-rich formula helps in protection against sebum oxidation thus preventing damage to skin"s protective barrier. Whitening Source DermDefinition UV Lotion (SPF50) also contains SK-II"s unique ingredient Pitera which enhances skin"s overall condition. To Use: After cleansing toning and moisturizing the skin apply Whitening Source DermDefinition UV Lotion which provides protection from daily environmental stress.