Food and Drug Administration Commissioner Dr. Scott Gottlieb made his most direct threat yet against e-cigarette companies Friday, saying they face an “existential threat” if they don’t stop marketing to youth.

Gottlieb said he was horrified at the recent rapid rise in teen vaping. He called out the most popular product — Juul— by name and said his efforts to get companies to voluntarily dial back on candy-flavored products and heavy-handed marketing techniques were not having much effort.

The FDA has the power to stop e-cigarette sales and compel makers to go through the formal FDA approval process. The agency has not done this yet, much to the disappointment of groups such as the Campaign for Tobacco-Free Kids, the American Heart Association and the American Cancer Society Cancer Action Network.

Gottlieb said he is about ready to do so.

“I’ll tell you this. If the youth use continues to rise, and we see significant increases in use in 2019, on top of the dramatic rise in 2018, the entire category will face an existential threat,” he told a meeting.

“It will be game over for these products until they can successfully traverse the regulatory process.”

There’s little debate that vaping has hit record highs among children and teens. Last November, the figures from the Centers for Disease Control and Prevention found a 78 percent increase in vaping by high school students, with 3.6 million high school and middle school students now using e-cigarettes.

Gottlieb said he has met repeatedly with the vape industry. “I find myself debating with tobacco makers and retailers the merits of selling fruity flavors in ways that remain easily accessible to kids,” he said.

Last November, Gottlieb said he was starting the process to limit sales of flavored e-cigarettes, as well as to ban menthol in combustible cigarettes.

“I have questions about whether they are living up to the very modest promises that they made,” he said. “It matters if the e-cig makers can’t honor even modest, voluntary commitments that they made to the FDA.”

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I still believe e-cigarettes present an opportunity for adult smokers to transition off cigarettes and onto nicotine delivery products that may not have the same level of risks. However, if the youth use continues to rise, the entire category will face an existential threat — Scott Gottlieb, M.D. (@SGottliebFDA) January 18, 2019

Gottlieb was speaking at a hearing meant to gather input about how to help youth who are already addicted to the nicotine in e-cigarettes. Most experts there agreed that there is not much evidence about what might work, although several said it’s important to help teens with the anxiety and social pressure that go along with vaping.

But Dr. Susanne Tanski, a pediatrician and past chair of the American Academy of Pediatrics Tobacco Consortium, said even asking the question was distracting from the more immediate issue of keeping vapes away from teen and children.

“We must all recognize that if an adolescent has developed a nicotine addiction as a result of vaping, we have already failed,” Tanski told the hearing, held at FDA headquarters outside Washington, D.C.

“Where we are, it’s huge, and they are addicted."

“FDA’s recently announced regulatory actions regarding e-cigarettes do not go far enough and we urge much stronger action. Strong tobacco control policy aimed at keeping enticing products away from adolescents may be more effective in achieving adolescent cessation than medical interventions,” she added.

“There is unfortunately virtually no data on how to treat an adolescent with e-cigarette dependence. As things currently stand, there is not a single randomized controlled trial that has tested strategies to help teens quit e-cigarettes, and there is a significant need for research in this area. We simply do not know yet if our traditional approach to cigarette cessation will apply to adolescent vaping cessation.”

It will take years before the studies are done that answer the question of what works to help people addicted to e-cigarettes, which often deliver nicotine in huge doses and in formulations that may make them even more addictive than traditional cigarettes.

“FDA is asking the wrong questions,” Lauren Lempert, a researcher at the University of California San Francisco’s Center for Tobacco Research and Education. “E-cigarettes are recreational products, not drugs. Let’s face it — kids think e-cigarettes are cool and they use them as recreational products.”

Lempert said the FDA should focus on stopping adolescents from ever using e-cigarettes at all.

“FDA should fulfill its legal mandate and immediately pull from the market all e-cigarettes that have not been pre-approved,” she said. “They should prohibit all internet sales of e-cigarettes.” Age verification schemes do not work, she said, and teens find ways to buy vapes online.

Let’s face it -- kids think e-cigarettes are cool and they use them as recreational products.”

Dr. Bonnie Halpern-Felsher, who studies youth e-cigarette use at Stanford Children’s Health, agreed all sales of flavored vape products should be eliminated. “There is no evidence that adults need these flavors to quit smoking,” Halpern-Felsher told the meeting.

But she said the FDA is also helping to muddy the waters by saying e-cigarettes are safer than combustible tobacco products. “We need to stop saying that e-cigarettes are safe or safer and prevent e-cigarette companies from making these unauthorized risk claims,” she said. “Youth hear them. We need to stop saying that e-cigarettes help adults stop smoking when there not clear evidence that this is the case.”

Plus, these statements confuse teens and children. “That is giving them the idea that they are therefore safe and okay to use,” she said.

Juul and other e-cigarette makers have said they are working to keep their products away from teens and children. Juul has launched an advertising campaign to point out that e-cigarettes are for adults only.

Lempert said that only makes vaping more seductive to teens. “Adults-only messages attract kids,” she said. The tobacco industry has long used the forbidden fruit message to hook new smokers, she said.

“I feel like we're living in the past,” agreed Anne DiGiulio of the American Lung Association. “The e-cigarette companies are taking plays out of the cigarette companies’ playbook,” DiGiulio told NBC News. “You see it with their advertising. You see it with the appealing to kids, flavors, everything. It is incredibly frustrating to see.”

Warnings on the packaging and in ads also do not work, said Halpern-Felsher. “Warnings on packets are not understood by adolescents,” she said. She’s studied teenagers, asking them what such warnings mean, and she said they do not interpret them correctly. “Youth don’t understand addiction,” she said. “They don’t understand that this means they will not be able to stop using these products when they want to.”

Experts on smoking cessation said it takes time and is difficult. Don Seibert, who owns Smokenders in Birmingham, Alabama, says his program has only a 60 percent success rate.

“The younger someone starts using a tobacco product, the more difficult it is for them to quit,” DiGiulio said. “We have a program to help kids quit. But with this new epidemic, we need more than just counseling.”

RuthAnne McCormack of the Rockville Centre Coalition for Youth on Rockville, Long Island, said the problem is out of control. “Where we are, it’s huge, and they are addicted,” she said.

“They start as young as the 4th grade,” she added. “Although the e-cigarette companies promised they would remove the fruit and other flavors, in our brick and mortar stores they are still available and the stores that sell them do not ask for ID.”

She asked the FDA to do anything it could to help. “The kids say to me, ‘I’m not addicted’ and they have been vaping for maybe five or six years,” McCormack said. “They get agitated, they get anxious, they get nervous, they can’t sleep. They need help. And we need to stop it.”