The antioxidants in vitamin C may help defend against the damage that UV light can cause.  That doesn’t mean that you can use a vitamin C skin serum in place of sunscreen. It can’t replace SPF since it doesn’t absorb UVA or UVB rays. But if UV light does get into your skin, some research suggests that vitamin C can help blunt the harm.
Vitamin C-based skin care products may lighten patches that are darker than the rest of your skin, called hyperpigmentation. In one study, vitamin C applied to the skin for 16 weeks significantly cut down on these spots. But experts say it will take more research to confirm how well vitamin C topicals work.
 
Smooth out those wrinkles.
Helps to lighten dark spots.
Boosts Collagen
Promotes Healing
 Webmd has some great info right here: