I've tried a LOT of vitamin C serums out there. I've used Timeless (2 bottles), Derma E, Mad Hippie, DE, etc. They weren't all bad, but I didn't see any improvements and some made my skin red and blotchy. Skinceuticals was going to be my last attempt at Vit C and it's been an awesome experience. II was developing some crepe-y skin on my forehead and the crows feet on the corners of my eyes were starting be be more noticeable. Within a few weeks of using this, the crepey skin firmed up a bit and was less noticeable. My crows feet seemed to have softened lines look a bit "shorter" than before.