I'm confused about vit C - can anyone help?

[Feedingthebirds1]

Vitamin C is everywhere in skincare, we're told it brightens, neutralises free radicals, protects against oxidation etc.

Yet in the same articles, they emphasise that it isn't photostable, and has to be carefully packaged to minimise exposure to light and air because exposure causes it to oxidise and form...free radicals.

Please can anyone explain?

The best analogy for this I've seen is that you have to view vitamin c like the airbags of your skincare routine. Instead of free radicals attacking the health of your skin by way of oxidative stress (sun, environment, smoking, etc.) an antioxidant like vitamin c will oxidise in its place, protecting you from (free radical) harm.

More in depth discussion of it by a cosmetic chemist here although the whole role of an antioxidant in an oxidative process is summarised in a diagram which probably isn't all that explanatory if you're not very scienc-y, rest of the article is good though.

Thank you. The article really explains it (and the diagram, I did chemistry A level!)