The Best Sources of Caffeine—Revealed

A Sure Jolt: Brewed Coffee

Coffee, plain or fancy, is most people’s go-to for a burst of energy, and for good reason—a single cup contains about 100mg or more of caffeine, depending on the roast. A good rule of thumb is the lighter the roast, the more caffeine it’ll contain. Some iced coffees are highly concentrated, too. Learn how to make your own cold brew.

Good to know: Coffee takes about 20 minutes to take effect. Try to keep tabs on how much coffee you’re drinking. If you knock back more than four cups a day and start to feel jittery or have trouble sleeping, consider switching to half-caf or decaf in the afternoons and evenings. These are the 7 signs you’re drinking too much coffee.