FDA is cracking down on powdered pure caffeine, which has been linked to two deaths in 2014, sending warning letters Tuesday (Sept. 1) to five dietary supplement distributors that sell the product, advising them that serving size information on their labels makes their products a safety risk. The agency, which notes one teaspoon of powdered caffeine is roughly equal to 28 cups of coffee, first addressed the dangers of the product in a consumer warning last year following the deaths...