FDA has sent warning letters to five distributors of powdered caffeine, claiming that the companies are selling dietary supplements that present “a significant or unreasonable risk of illness or injury.” Consuming 1 teaspoon, or about 2.7 g, of such powdered caffeine products is equivalent to drinking about 28 cups of coffee, according to FDA. Manufacturers recommend a maximum serving size of 200 mg, which FDA estimates is about 1/14 teaspoon. That amount, the agency says, is nearly impossible to measure accurately with common kitchen tools. “The difference between a safe amount and a toxic dose of caffeine in these pure powdered products is very small,” FDA warns. In a separate move, FDA also sent warning letters to three cigarette manufacturers for using the words “natural” and “additive-free” on their packaging. Such claims lead consumers to believe the products pose fewer risks than other tobacco products, FDA says. Manufacturers must provide FDA with scientific evidence to support such claims.