Descriptions Your skin deserves all the protection you can give it. Especially from daily exposure to the sun's damaging rays and environmental assaults that can prematurely age skin. With Obagi's Professional C Serum, you can give your skin the protection it needs. Product Ingredients Ascorbic Acid, Propylene Glycol, Water, Propylene Carbonate, Fragrance Suggested Use Apply a few drops to your face, neck and chest in the morning. If you are using the Obagi Nu-Derm line, apply after the Toner in the morning. If you are using the Obagi C-Rx line, you will want to replace it for the C- Clarifying Serum to boost the Vitamin. Note Obagi System skin care products are prescription strength, or pharmaceutical quality products that work at the cellular level to improve the skin cell function. It is important to contact your Physician or Skin Care Specialist prior to use and purchase. Weight 1 fl oz/ 30ml