Caffeine

Caffeine has become a popular ingredient in skin care products ranging from under-eye serums to face masks to anti-cellulite cream. It is an antioxidant, which is known to protect skin from damage caused by free radicals — molecules that break down your collagen and wrinkles.

Caffeine is a vasoconstrictor, which means it makes the blood vessels constrict, or tighten. That, in turn, reduces blood flow to the skin and makes your skin look brighter and smoother.