Companies who are still selling pure caffeine powder after the Food and Drug Administration warned against the product over the summer could face legal action if they don't stop soon. 

Caffeine powder is unregulated because the FDA doesn't have the authority to pull from shelves a substance such as the powder - which is dangerous even in small doses - reported The Associated Press. One teaspoon of caffeine powder is the equivalent of 25 cups of coffee.

Caffeine powder is regulated when consumed in products, such as soda, but not when the chemical is sold alone. 

Consuming too much of this caffeine is deadly, as America saw when the powder took the life of a teen from Ohio and a man from Georgia earlier this year. 

Michael Taylor, the FDA's deputy commissioner of foods, told AP that marketing such a potentially dangerous product is "inherently irresponsible." 

After the Ohio teen died from consuming too much of the powder, which is marketed as a dietary supplement, the warned consumers to stay away from it. After the warning some major retailers stopped selling it, although it is still available in some stores and online. 

"I would hope that people would get the message that they just ought to stop selling it," Taylor said to AP.

The agency plans to "pursue all legal options" against those still selling the powder, although it did not release a timeline for this legal action.