Caffeine solution 5% + egcg is an effective, water-based serum that targets dark circles and puffiness around the eyes, promoting under-eye brightening. Formulated with a 5% concentration of caffeine and epigallocatechin gallatyl glucoside (egcg), this potent serum helps improve the look of tired eyes while providing a brightening effect. Caffeine works to reduce puffiness, while egcg works to help reduce the appearance of dark circles.