Although coffee is now basically considered a superfood, its most electric component—caffeine—can be deadly when consumed in powdered form. Last year, in fact, two young men died after overdosing on the substance, which can be bought legally.

The Food and Drug Administration on Tuesday warned the public of these dangers while sending letters to five distributors of powdered caffeine saying their product presents a "significant or unreasonable risk of illness or injury to consumers." The reason they're so dangerous, the FDA said, is because it's so easy to mistakenly take a toxic dose.

"The difference between a safe amount and a toxic dose of caffeine in these pure powdered products is very small," the letter said. "Furthermore, safe quantities of these products can be nearly impossible to measure accurately with common kitchen measuring tools."

Powdered caffeine is sold in bulk primarily to make energy drinks at home. According to the FDA, one teaspoon carries as much as caffeine as 28 cups of regular coffee. 

"Ten grams, about a tablespoon, is a lethal dose for an adult," The New York Times reported in May. "A 100-gram package—as much caffeine as 400 "tall" cups of Starbucks coffee, 1,250 Red Bulls, or 3,000 cans of Coke—costs about $10."

Side effects of powdered caffeine may include rapid or dangerously erratic heartbeat, seizures and death, the FDA said. A high school student in Ohio and 24-year-old recently married college grad in Georgia both died after overdosing on powdered caffeine within weeks of each other last year, according to the Times.

The first warned consumers of the dangers of powdered caffeine in the wake of these deaths, issuing consumer advice on the matter.

Follow Delish on Instagram.