Skin Ceuticals Serum 10 AOX+

Dispense 4–5 drops of this antioxidant serum onto a dry face, neck, and chest as the first step before your other skincare products — the backs of the hands can benefit too. If the formula deepens in color after opening, don't worry; this is a normal reaction of vitamin C to air and light and doesn't affect its performance, though it's best used within three months of first opening. Round out your routine with a SkinCeuticals sunscreen — combining their antioxidants with a broad-spectrum SPF provides fuller protection against visible aging driven by environmental stressors.