Topical Vitamin C is one of the most important ingredients that should be applied to the skin. Why? During the day, we are exposed to “oxidative stress” in the form of UV exposure, pollution and environmental factors such as smoking (even if it is second hand smoke). All these oxidative assaults can prematurely age our skin. Certainly, wearing sunscreen is very important, but we must do more than simply wearing sunscreen. I highly recommend applying a topical antioxidant such as Vitamin C on the skin in the am and pm.
Humans do not produce Vitamin C, therefore it is important to take in Vitamin C either orally or topically. To have adequate concentrations in the skin, the only way to truly get there is via topical application.
It is equally important to note that not all Vitamin C serums are equal. My favorite Vitamin C serum is Skinceuticals Vitamin C/E and Ferulic Acid. The reason for this has to do with the science behind the formulation. Skinceuticals has patented the pH of the Vitamin C formulation between 2.5 to 3.0. The reason is that you need for a pH of the Vitamin C to be below 3.5 which indicates that it is not protonated and therefore can actually penetrate the stratum corneum. Many formulations on the market today have too high of a pH which will therefore not penetrate past the stratum corneum, or too low of a pH which causes unnecessary redness/irritation and pseudo allergy to the skin making it intolerable to apply.
For proper depot levels to be obtained on the skin, topical Vitamin C should be applied in the am and pm. The product is a liquid and I typically place a couple of drops in the base of my hand and then apply to the face. Any residual amount, I will rub on the back of my hands as this area also can become photodamaged.