I also use Hyaluronic acid and natural rose hip seed oil (pure retinol) in my serum and its awesome. The ultra wonderful l-ascorbic is so g=hard to find domestically. I bought 90g for 27 USD (transport and all) little bit dear but it surely goes a good distance. Michelle D. https://7figurebm.com/how-to-make-vitamin-c-serum-from-orange-peel/