La Roche-Posay Pure Niacinamide 10 Serum is their first 10% niacinamide concentrate. The serum consists of a powerful dermatologically tested formula that contains 10% niacinamide and 5% HEPES (gentle exfoliator). The formula also contains hyaluronic acid that helps retain the skin’s natural moisture. The formula has been tested and re-tested on even the most sensitive skin and it has undergone multiple dermatological tests.