So you’ve been doing some revenge bedtime procrastination and it shows. We can’t fix your sleep deprivation, but the best caffeine eye cream can do something about those undereye bags and dark circles. “Caffeine works to reduce puffiness by clamping down on blood vessels, helping to reduce swelling,” Marisa Garshick, MD, FAAD, a board-certified dermatologist in New York and clinical assistant professor of dermatology at Weill Cornell Medicine, tells Glamour.