COLUMBUS, OHIO- The FDA issued warning letters to five distributors of powdered caffeine warning them they put users at risk or getting sick or being hurt.

They follow the deaths of two young men who died of overdoses in Georgia and Ohio. The FDA claims one teaspoon of pure powdered caffeine ids almost equivalent to 28 cups of coffee.

The FDA says the pure powdered caffeine contains thousands of servings and claims the quantities in the packages are potentially lethal to people.

The FDA says a safe amount can be nearly impossible to  measure with common kitchen tools and it warned consumers last summer to avoid the pure powdered caffeine.