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Next month in the U.K., anyone at a major grocery store looking to buy a soft drink with more than 150 mg of caffeine per liter will need to present an ID. Stephane Grangier/Getty Images hide caption

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Stephane Grangier/Getty Images

One teaspoon of pure caffeine powder delivers about the same jolt as 25 cups of coffee. The Center for Science in the Public Interest hide caption

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The Center for Science in the Public Interest

Potent Powdered Caffeine Raises Safety Worries

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The bar at a surprise birthday party for Teen Wolf's Stephen Lunsford, presented by Monster Energy last November in Los Angeles. Todd Williamson/Invision/AP hide caption

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Todd Williamson/Invision/AP

U.S. Army Pvt. Freymond Tyler sleeps on a laptop next to his gun at combat outpost Makuan in Kandahar province, Afghanistan, in 2011. Romeo Gacad/AFP/Getty Images hide caption

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Romeo Gacad/AFP/Getty Images