Last summer, two young adults died after ingesting powdered caffeine, leading the Food and Drug Administration to warn consumers of the potential hazards of the popular stimulant while public health advocates called for a ban on the powdered product. Now the FDA is taking things to the next level and warning caffeine manufacturers that their products are “dangerous and present a significant or unreasonable risk of illness or injury.”

The FDA announced today that it has sent letters to five different companies, letting them know that continued sale of their products as “dietary supplements” with their current labeling and usage instructions could result in seizure by the agency.

One of the repeated themes in the letters is the potency of powdered caffeine and the difficulty consumers have with measuring amounts recommended on product labels.

For example, one product label provides the following instruction: “As a dietary supplement, take 50 to 200 mg up to three times daily. Use an accurate milligram scale for measurement.”

First, the FDA notes that most consumers don’t have scales precise enough to accurately measure this tiny amount. And if you want to take a volumetric approach to measuring, you get into sizes like 200mg of the powder equaling about 1/14 of a teaspoon, which is not an option you find on the measuring spoons in most kitchens.

Other products were cited for instructing users to ingest a “rounded 1/32 teaspoon,” which is both a imprecise measurement and an uncommon measuring spoon size.

And if users of these products do turn to common measuring devices they run the risk of doing real damage says the FDA.

“A single teaspoon of pure powdered caffeine is roughly equivalent to the amount in 28 cups of coffee,” writes the agency. “Consuming as little as one teaspoon of caffeine has been associated with symptoms including nausea, vomiting, anxiety, and heart palpitations.”

Make the common mistake of confusing a teaspoon and a tablespoon and you’re tripling the amount of caffeine ingested. The FDA says this level of consumption has been associated with symptoms including chest pain, hypokalemia, elevated blood glucose, tachycardia, bigeminy, agitation, respiratory alkalosis, irregular heartbeat, and death.

Another problem with some powdered caffeine products is the size of the packaging. Given the small amount of caffeine per recommended dose, a 10 kg package contains around 50,000 servings. One product was sold in a 25 kg package, equivalent to anywhere from 125,000 to 500,000 servings of that particular product.

The companies have 15 days to reply to the FDA with details of how they are planning to address the violations cited in the warning letters. If violations continue, the FDA could take further action and seize products.

The Center for Science in the Public Interest, which has petitioned the FDA to ban the retail distribution of powdered caffeine, says today’s FDA announcement is a first step in the right direction.

“Pure caffeine never should have been sold to consumers,” says CSPI Regulatory Affairs Director Laura MacCleery in a statement. “A teaspoon is a fatal dose for a child, and two teaspoons would kill most adults. FDA has clear authority to ban such a hazardous product and should do so.”

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