From the brand that's known for doling out one game-changing sunscreen after another, Supergoop! is calling the new Daily Dose Vitamin C + SPF ($46, available Dec. 28) its most innovative SPF formula yet. That's because this serum-sunscreen hybrid packs a heavy punch of vitamin C (a compound that is notoriously tricky to formulate around, thanks to its unstable chemical makeup), making it a first of its kind.