http://effective-skin-care.com/blog/vitamin-c-skin-care/
Best vitamin C E skin care products
Vitamin C skin care?
I took a biology class and I learned that vitamin C is water soluble. Therefore, can not cross the cell membrane, which means it can not be applied to the skin as it does not work. And there are many Vitamin C skin care because they can not cross the membrane of the cell, does not mean it works, and why the shops still there?
You're right. You benefit from taking vitamin C when taken internally and is metabolized. As for cosmetics, is to do more marketing. You are an informed buyer, but there is not much to you. After 8 years in the pharmacy, the health of your skin is mainly determined by genes (although the skin seems to run in families) and other things like the amount of collagen in the skin (again, that related genes), hydration (maintenance fluids), and limit sun exposure (sorry, the surfers, but you are generally not to die for skin). 
