Overworked and sleep-deprived, more people are using caffeine as an energy crutch than ever before, experts say. That's not all bad: In fact, 250 milligrams of caffeine per day -- that's two to three cups of joe -- wakes up the brain, improves concentration, relieves stress, and may also help you live longer. But if intake is turning into addiction, you may notice side effects, including dehydration, trouble sleeping, anxiety, an upset stomach, and even problems during prenancy.
If you're trying to cut back, you've probably already reduced the amount of coffee, tea, and sodas that you consume. But the sneaky stimulant can pop up in unexpected places. Since the U.S. Food and Drug Administration (FDA) doesn't require manufacturers to list caffeine content on nutrition labels, it's often hard to tell whether a product contains the stimulant, and how much. These 12 sources of caffeine -- some hidden, some just plain weird -- could be giving you the jitters.