Yet very little research about e-cigs has homed in on the Juul specifically.

So for a study published this week, researchers from the Stanford University School of Medicine surveyed young people who vaped and asked them whether they used the Juul or another e-cigarette.

Their results can be found in a widely accessible version of the Journal of the American Medical Association called JAMA Open. Based on a sample of 445 high-school students whose average age was 19, the researchers observed that teens who used the Juul tended to say they vaped more frequently than those who used other devices. Juul users also appeared to be less aware of how addictive the devices could be compared with teens who vaped other e-cigs.

“I was surprised and concerned that so many youths were using Juul more frequently than other products,” Bonnie Halpern-Felsher, a professor of pediatrics who was a lead author of the study, said in a statement.

“We need to help them understand the risks of addiction,” she added. “This is not a combustible cigarette, but it still contains an enormous amount of nicotine — at least as much as a pack of cigarettes.”

Erin Brodwin/Business Insider