The Food and Drug Administration has issued warning letters to five distributors of pure powdered caffeine, saying the products put consumers at risk. Caffeine powder is usually marketed as a dietary supplement and is unregulated, unlike caffeine added to soda. Since the FDA doesn't have the legal authority to pull such a substance off the shelves, the agency has been building a case against those who are marketing it in bulk in an attempt to persuade them to stop. Last summer, the FDA warned consumers to avoid pure powdered caffeine, which some users add to drinks for a pick-me-up before workouts or to control weight gain, after the death of an 18-year-old high school wrestler in Ohio.
A teaspoon of pure powdered caffeine is roughly equivalent to 28 cups of coffee, according to the FDA. The difference between a safe and toxic amount is very small, and a safe serving can be nearly impossible to measure with common kitchen tools. "Volume measures, such as teaspoons, are not precise enough to calculate how many milligrams of caffeine are in the serving size," the FDA says. The packages of pure caffeine referenced in the warning letters contain hundreds or thousands of servings of the stimulant, which the FDA says could be lethal to consumers. Three of the five companies stopped selling the powder after receiving the FDA letter, while another says it's preparing its response to the FDA and a fifth has yet to comment. (Read more FDA stories.)