Obagi-C Fx System Clarifying Serum is a humectant-based serum that corrects and protects. This serum reduces the appearance of dark spots and works to give skin a lighter, brighter more even complexion. Active ingredients include 10% pure L-ascorbic Acid (Vitamin C) which reduces the appearance of dark marks and stimulates collagen production which helps with signs of aging. It also provides antioxidant protection against environmental stressors that cause damage to the skin. 4% Arbutin reduces the production of melanin which causes dark marks and also assists with better absorption and penetration of the serum. Suitable for use on all skin types except Sensitive and Rosacea-prone skin.