The death of an Ohio high school student has led the U.S. Food and Drug Administration to announce it's investigating widely available caffeine powders and may consider regulatory actions.
Caffeine powder, easily available for purchase online, is often added to drinks before workouts as a pick-me-up and as a means of controlling weight gain.
The drug is being blamed in the death of Logan Stiner, a wrestler and student who died at home in LaGrange near Cleveland.
An autopsy revealed Stiner had a lethal amount of caffeine in his system at the time of his death, around 70 micrograms per milliliter of blood.
That's more than 20 times the level present in a typical drinker of coffee or sodas, a report by the county coroner said.
The powder is almost 100 percent pure caffeine, the FDA says, with a teaspoon of it containing the caffeine equivalent of 25 cups of coffee.
As little as 5 to 10 grams of the powder could be a lethal dose, the agency says.
On its website, the FDA lists symptoms of a caffeine overdose as including dangerously erratic or rapid heartbeat and seizures.
Signs of caffeine toxicity also can include diarrhea, vomiting, lethargy and disorientation, it said.
Although many sellers of the caffeine concentrate caution against using more than a 1/32nd or 1/16th of a teaspoon of the powder, it is nearly impossible to measure out a dose accurately using common kitchen implements, the FDA said. Just a 1/16th teaspoon dose is the equivalent of 2 large cups of coffee, or about 200 milligrams of caffeine.
"The difference between a safe amount and a lethal dose of caffeine in these powdered products is very small," FDA spokeswoman Jennifer Dooren says.
Health officials and physicians have expressed concern over the powder's popularity among young people. Some exercise enthusiasts turn to it as an energy booster and some young people see it as a quick way to drop pounds. It is sold as a dietary supplement.
"They're starting to latch onto the powders more because they see it as a more potent way to lose weight," says Dr. Dr. Robert Glatter, an emergency physician at a New York Hospital.
In the last few months he's seen several younger patients suffering complications from caffeine overdoses, he says, many of them arriving in the ER with rapid heart rates.
The dangers of caffeine can easily be overlooked because it is so ubiquitous, experts say.
"The thing about caffeine is just because you see it every day, just because it's naturally occurring -- it comes from a plant -- doesn't mean that it's safe," says Dr. Bob Hoffman, a New York University medical toxicologist.