Besides boosting the body’s energy levels when ingested, caffeine may rejuvenate the skin when applied topically. Researchers repeatedly exposed mice to UVB light and applied either a caffeine or placebo cream.

The caffeine doubled the rate at which UV-damaged skin cells were cleared from the body — and after 11 weeks, the treated mice had fewer wrinkles than the others.

Research has also shown that topical caffeine helps prevent skin cancer in UV-exposed mice, says Paul Ngheim, associate professor of dermatology at the University of Washington, but human studies are needed.

Skin-care products with green-tea extract may contain caffeine. A coffee-plant extract called CoffeeBerry (in RevaleSkin cream) contains only trace amounts of caffeine but has also been shown to diminish wrinkles. [source: Allure]