On 5/13/2016 at 6:48 AM, GuevaraBeats said:

Make your own. Vitamin C is very unstable and they don't have a long shelf life so many of the vitamin C sellers online will give you an oxidized serum that's no good. Always look for yellowing if so the serum is oxidized. there was a study on pubmed where the docs would go back and fourth with needling and doing tca peel every 2 weeks.

There's stable forms of vitamin C. You're referring to l-ascorbic acid.Ascorbyl Palmitate is stable.