I had heard a lot of wonderful things about the original C20 Pure Vitamin C serum, but I never purchased it.  When C20 came out with a new and improved version, C21.5, I was very interested in trying it out.  Wishtrend.com graciously sent me the C20 Pure Vitamin C21.5 Serum and I have been using … More C20 Pure Vitamin C 21.5 Advance Serum Initial Impressions