Vitamin C or ascorbic acid is well-known for its anti-oxidant properties, effectively neutralizing the dangerous effects of free radicals.  Similarly, its ability to promote collagen synthesis makes it an important co-factor in skin damage and repair, according to Medical News Bulletin.

Scientists have also found that it can seal blood vessels and limit the deposition of pigment.  Taking all these properties into consideration, Vitamin C preparations are being looked at as treatments for capillary skin.