SkinCeuticals Discoloration Defense SerumSkinCeuticals Discoloration Defense is a layerable, daily use dark spot corrector clinically proven to reduce key types of skin discolouration. Formulated with 1. 8 % tranexamic acid, 5 % niacinamide and 5 % HEPES, it tackles brown patches, post blemish marks and dullness to reveal a brighter, more even toned complexion. This lightweight serum absorbs quickly without greasy residue and can be worn alone or under your favourite moisturisers and SPF.