Ice cream, lip gloss, and sparkling water are just a few of the products that can contain neotame — an artificial sweetener that’s 7,000-13,000 times sweeter than sugar. Now researchers have found it’s also in many flavored disposable e-cigarettes, which they warn gives them extra appeal to teens and kids.

The study, published Monday in JAMA, found neotame in all 11 of the popular disposable vape brands it tested, including Elf Bar, Breeze, and Mr. Fog. Neotame was also detected in vapes marketed as “zero-nicotine” or that used nicotine analogs. All of these vapes are technically illegal in the U.S., but remain widely available at many gas stations and convenience stores as well as online. The study did not find neotame in the four e-cigarettes it tested that are authorized for sale by the Food and Drug Administration, nor in Juul, which has an application pending with the FDA. 

The U.S. market is awash in illegal e-cigarettes in fruity flavors like “Killar Kustard Blueberry,” which make up 86% of retail sales in the U.S., according to anti-tobacco use nonprofit Truth Initiative. The vast majority of these products are imported from China, which banned the domestic sale of flavored vapes in 2022, spurring companies there to turn their focus to the U.S. and other foreign countries. The FDA has authorized just 34 tobacco- and menthol-flavored e-cigarettes so far, which account for 14% of retail sales. The Supreme Court last month upheld the FDA’s refusal to authorize flavored vapes over concerns about the products’ allure to young people.

 “We think that the presence of neotame is really a determining factor in the attractiveness and preference for these products,” said Sven Jordt, one of the study’s authors and an associate professor in pharmacology and cancer biology at Duke University School of Medicine. That’s particularly true for children and teens, he said, who crave intensely sweet tastes much more than do adults. 

While vaping rates have fallen among U.S. youth, e-cigarettes are still used by 5.9% of middle- and high-school students, making them the most popular tobacco product among that age group, according to a 2024 government survey. The survey also found that flavored, disposable vapes are the types of e-cigarettes most favored by that age group. Public health experts are particularly concerned about vaping among youth because nicotine harms developing brains, and because the habit may put them at higher risk for smoking cigarettes later on or developing other addictions.

Researchers also warn of an additional problem with neotame in e-cigarettes: The sweetener is only FDA-approved for use in food. “We don’t know how safe they are if you inhale them into your lungs,” said Jordt. Many cigarettes, for example, contain added sugar, which helps mask the bitter flavors in tobacco smoke. But when that sugar is burned, it increases the levels of toxic chemicals that people inhale. 

Nicotine pouches like Zyn and chewing tobacco also contain sweeteners, which other researchers have argued allows them to be classified as “unflavored” while still imparting a distinctive taste. The Tobacco Control Act does not mention sweetness levels in its definition of flavors.

Mitch Zeller, a former head of the FDA’s Center for Tobacco Products, said the study raises a separate thorny question: Does the FDA actually have the authority to regulate some of these products? 

Nicotine analog products use compounds that have a different chemical formula than nicotine, but are quite similar. The nicotine content in the analog products tested in the study was zero. A number of health organizations and advocacy groups have raised concerns that brands like Spree Bar are using nicotine analogs in an effort to evade regulation, under the argument that they’re not technically tobacco products as defined in the Tobacco Control Act. 

The Trump administration has said it plans to crack down on illegal vapes, and recently announced the seizure of $34 million worth of the products in Chicago. Discussing the seizure in public remarks in late May, FDA Commissioner Marty Makary warned, “I personally have observed kids from good families who have become addicted to vaping,” and said that products imported from China “may have risks we have yet to understand as a medical profession.” 

But both Zeller and Jordt noted that the shuttering the Office of Smoking and Health at the Centers for Disease Control and Prevention and cuts to the FDA’s Center for Tobacco Products are at odds with the goal of a strong government response to illegal vapes. 

“While the research highlights important questions from a toxicological and abuse liability standpoint, the sheer size of the illicit e-cigarette market needs addressing,” Cristine Delnevo, director of the Rutgers Institute for Nicotine and Tobacco Studies, said via email. The FDA needs to authorize the e-cigarettes that meet it standards, she said, and take enforcement actions against the ones that don’t.

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