E-cigarettes may be as addictive as regular cigarettes, a new study suggests.
Researchers tested samples of e-liquids and found that much of the nicotine in e-cigarettes is the addictive form of the compound.
The study calls into question e-cigarettes' usefulness in helping people quit smoking traditional cigarettes, CBS News reports.
Najat Saliba of the American University of Beirut also found the concentration of nicotine varied, often not matching the amounts listed on product labels.
The study appears in Chemical Research in Toxicology.
Dr. Daniel Neides, Medical Director of the Cleveland Clinic Wellness Institute, told CBS News the study suggests non-smokers who start using e-cigarettes could become addicted to nicotine. "Another major concern is that are the higher concentrations of nicotine going to increase the risk for patients going from the e-cigarettes to regular cigarettes," he said.
E-cigarette use among teens tripled from 2013 to 2014, according to a government report released earlier this year. An estimated 13 percent of high school students used e-cigarettes last year—compared with 9 percent who smoked traditional cigarettes.
The report, from the Centers for Disease Control and Prevention, found about one-fourth of high school students and 8 percent of middle school students used tobacco in some form in 2014. Between 2011 and 2014, the share of high school students who smoked traditional cigarettes dropped from 16 percent to 9 percent.