I had been hearing the most insane things about the Westman Atelier Vitamin C Serum. The before/afters are wild, and it is just one single ingredient, apparently from Japan, that Gucci was obsessed with. I could not justify spending $325 for LESS than 1oz. I found the supplier, and you can order direct from them. This concentrate is amazing. It's a very thick, oil consistency, and after 1 week of daily use I noticed a difference in appearance of my tone and pigmentation. I use in the am and follow with SPF. No moisturizer necessary as this is v hydrating.