Vitamin C is a powerful substance for repairing and protecting the skin. Most topical vitamin C preparations are of little use, however, because vitamin C is unstable, meaning that it is a delicate molecule, readily damaged. Once vitamin C is damaged it cannot penetrate the skin or perform any of its essential roles. Taking vitamin C orally does not result in sufficiently high concentrations in the skin to optimally lessen the signs of aging or protect the skin. Obagi's vitamin C serums are stable and quickly absorbed by the skin where they play a number of beneficial roles such as:

• Neutralizing harmful chemicals called "free radicals" which damage skin cells, collagen, elastin and DNA.
• Through its ability to neutralize free radicals, vitamin C protects the skin against ultraviolet rays which cause premature aging and skin cancers.
• Vitamin C both promotes the formation of new collagen and protects the skin's existing collagen.
• New collagen helps restore the skin's elasticity, reducing fine lines.
• Protecting collagen and elastin which helps prevent premature aging.
• Vitamin C helps to fade brown spots for more even skin tone and brightens the skin.
• Vitamin C regenerates vitamin E which is another important protection against free radicals.

10% — for dry skin

15% — for normal skin

20% — for oily skin