Obagi's Professional C 15% Serum blankets the skin in potent Vitamin C every morning. Formulated with 15% L-Ascorbic Acid, this impressive antioxidant treatment protects the cells against daily damage while dramatically boosting collagen production and correcting uneven tone at the surface. When used daily, this serum provides a high level of protection against environmental stressors and free radicals, shielding the skin from their effects and therefore successfully minimising the early signs of ageing. Suitable for all skin types, apply five to seven drops of the serum to cleanse the skin on the face, and neck and decollete using your fingertips. Use in the morning and always follow with sunscreen.