This serum is very effective to brighten and tightening my facial skin without any irritation I think it's from the new type of Vit C that contained in this serum (aminopropyl ascorbyl phosphate). In addition the texture is light enough to use it underneath my daily sunscreen cream and it enhances the sunscreen to the maximum through the day . I absolutely love it after using for 2 weeks and will surely repurchase it for such a great serum with worth price.