Dermatologists have long recommended vitamin C for brighter, healthier skin. Boosted by the skin care industry, vitamin C serums generate billions in annual sales. But the growing body of literature suggests that reality is more complicated than marketing claims suggest.
Without a doubt, vitamin C is essential for human skin. Studies found that normal skin contains a high concentration of the vitamin, with epidermal levels two to five times higher than in the dermis.
There are several functions associated with the compound, including serving as a cofactor for collagen synthesis, acting as an antioxidant against radicals formed by ultraviolet rays, suppressing melanin, and stimulating the formation of ceramides, the lipid molecules that bind skin cells together.
However, the real problem is getting the vitamin C to the skin.
Being a charged and water-soluble nutrient, it is very likely to be repelled by the surface of the skin. Beneficial penetration only occurs when formulations have a pH less than 4.
For better stability and penetration, manufacturers often use derivatives such as magnesium ascorbyl phosphate, ascorbyl glucoside, and ascorbyl palmitate. However, they need to be converted into active vitamin C once inside the skin.
Most serums never penetrate deep enough to work. Those that do only have three things, among them:
- Pure vitamin C (L-ascorbic acid) at low pH.
- They come in opaque, airtight bottles to prevent oxidation.
- Often combine vitamin C with vitamin E for best results.
But if vitamin C levels are already saturated through diet or oral supplements, topical application may not boost skin levels further.
