The scientific question behind the FDA crackdown on Juul and vaping

Introducing Grid Health, our new weekly health and policy newsletter

The tricky scientific question underlying FDA’s crackdown on Juul and vaping

The Food and Drug Administration’s decision last week to ban Juul’s vaping products illustrates how much of a conundrum electronic cigarettes pose to regulators.

Hear more from Jonathan Lambert about this story:

The products’ sleek design, kid-friendly flavors and aggressive marketing by companies like Juul drove millions of kids and teens to try the devices over the past decade, addicting many to devices with unclear long-term effects that can sometimes cause significant lung injury.

Yet e-cigarettes also present an opportunity to drastically reduce the public health toll of smoking. Compared with traditional cigarettes, electronic versions are clearly the lesser evil. Many experts view them as a powerful smoking cessation tool that could ultimately save millions of lives.

The trick for the FDA is finding the balance between those competing considerations — something it is legally required to do under a 2016 law that directs the agency to consider how tobacco products affect public health as a whole. The agency must also act based on incomplete evidence, since research into e-cigarettes is at an early stage and any long-term health impacts can’t be definitively known for decades. The FDA’s Juul verdict, its biggest move yet on vaping, was both praised and criticized by public health experts.


“This is a really tough issue that needs to be considered carefully,” said Michael Siegel, a public health researcher at Tufts University. “You have tremendous benefits and tremendous risks.”

Despite the steady decline in smoking over recent decades, it remains the leading cause of preventable death in the U.S., killing more than 480,000 people each year. E-cigarettes, if broadly adapted, could prevent many of those premature deaths. But they also threaten to create a new generation of nicotine addicts in the wake of smoking’s fall.

Here’s what the research on e-cigarettes currently says:

The good

E-cigarettes’ potential as a tool to reduce the harm of tobacco use for smokers stems from their ability to deliver nicotine — the addictive component of cigarettes — in a way that mimics smoking without all the cancer-causing chemicals.

“The theory is that e-cigarettes potentially provide a substitute for smoking,” said David Levy, a tobacco researcher at Georgetown University. While smoking is clearly harmful, “most experts would consider the harms from smoking at least five if not 10 or 20 times the magnitude of e-cigs.”


A National Academies of Sciences, Engineering and Medicine report from 2018 concluded e-cigarettes are likely to be far less harmful than traditional cigarettes, based on existing data. That’s largely because “many of the carcinogens are not present, and the toxins they have in common are generally lower,” said Neal Benowitz, a pharmacologist at the University of California, San Francisco. Toxicity varies by vaping device; the larger devices get hotter than smaller devices, thereby aerosolizing more toxic chemicals that can be found in the liquids in some pods, Benowitz said.

The limited data available suggests that e-cigarettes can be helpful for certain smokers. “If someone is motivated to quit and they switch to an e-cigarette and they vape daily, that’s shown to be effective to help them quit smoking,” Benowitz said.

A randomized clinical trial — the gold standard for evaluating medical interventions — in England found that 18 percent of smokers who used e-cigarettes for one year quit, compared with just under 10 percent of smokers who used nicotine patches. Given how difficult it is to quit smoking, many people likely try using e-cigarettes but fail to swear off traditional cigarettes entirely. For those who continue using both, “it can actually reduce quitting,” Benowitz said. “It really depends on how it’s being used and why.”

Other randomized control trials suggest quit rates are higher in people who use e-cigarettes, though not all studies found a benefit. Survey data also hints at a slight association between e-cigarette use and quitting, increasing quitting rates by about 10 to 15 percent.

“All these different kinds of evidence all lean in the same direction,” said Kenneth Warner, an economist at the University of Michigan’s School of Public Health. “Electronic cigarettes aren’t the be-all-end-all solution for smoking, but they’re pretty clearly a successful substitute for smoking for a subset of smokers.”


The data is less clear on how many smokers who quit using e-cigarettes also eventually quit vaping. Even if they don’t, the harm-reduction potential is huge, Levy said. If cigarette use in the U.S. were replaced by vaping over a 10-year period, Levy and his colleagues estimated 1.6 to 6.6 million premature deaths would be averted, assuming e-cigarettes have 5 percent or 40 percent the mortality risk of traditional cigarettes, respectively. “There’s potentially great benefits, both from a public health standpoint and an individual standpoint.”

Despite the enormous harm-reduction potential of e-cigarettes, nearly half of Americans think e-cigarettes are just as harmful or more harmful than traditional cigarettes, according to a 2020 survey from the National Cancer Institute. And e-cigarettes are of little use in reducing harm if smokers don’t understand the potential benefit of swapping their cigarettes for vapes.

The bad

But the data suggesting those potential benefits doesn’t stack cleanly up against evidence on the risks of e-cigarettes, especially for youth. Weighing the two ultimately requires the FDA to make a judgment about the value of keeping people off tobacco in the first place versus helping those who are already addicted to nicotine.

E-cigarettes came onto the U.S. market in 2007 and by 2014 were more commonly used than cigarettes by youth. Use among kids and teens reached a staggering peak in 2019, when more than a quarter of high school students reported using e-cigarettes. That meteoric rise was largely fueled by Juul’s aggressive marketing toward teens and has fallen a bit since then.

Most youth vapers weren’t smokers before trying e-cigarettes, so one major worry is that e-cigarettes could hook millions of kids to nicotine. Even though e-cigarettes are less harmful than traditional ones, nicotine addiction is obviously not good, said Benowitz.

“A big concern is that kids become compulsive users of e-cigarettes and have a hard time quitting,” he said. “Kids can have withdrawal in school and can’t pay attention, they’re spending their money on e-cigarettes, using them instead of doing other things in their lives.”

Juul and similar products use high concentrations of nicotine salts, which are less harsh to inhale than the nicotine in regular cigarettes and absorb quickly. That raises e-cigarettes’ addictive potential, Benowitz said. Each Juul pod contains about as much nicotine as a pack of cigarettes. When smokers vape with Juul, they often adjust how much they inhale to mimic smoking, Benowitz said. “Kids don’t have that experience with titrating, and there’s the potential for [them] to get exposed to more nicotine, faster.”

In laboratory animal studies, nicotine slows the maturation of the brain, associated with cognitive issues, greater substance abuse and impaired decision-making in adolescence. Scientists are still trying to figure out whether this is true in people; some studies suggest nicotine primes adolescent brains for future drug use.

Some vaping products can clearly damage the lungs. In 2019 and 2020, an outbreak of acute pulmonary disease linked to vaping killed 68 people and left nearly 3,000 with significant lung damage. Subsequent investigation tied about 85 percent of these cases to vitamin E acetate — an additive in some THC-containing e-cigarettes, while 15 percent reported using only nicotine-containing e-cigarettes. A year out from these injuries, many patients experienced cognitive impairment, respiratory limitations and other problems.

“We’re still learning about the harms these can cause,” said Denitza Blagev, a pulmonary critical care physician at Intermountain Healthcare. While most cases of severe lung damage are associated with THC-containing products, Blagev said vaping nicotine e-cigarettes can also cause problems. “Hypersensitivity, pneumonitis or other inflammatory reactions in the lungs can occur as a result of flavoring agents,” she said. “There’s also increased risk of susceptibility to infection.”


In adult smokers, such problems seem like a reasonable trade-off to the havoc smoked tobacco can wreak on the body. But the calculus is harder to swallow for many when kids are included. “When considering the availability and the marketing of those products, it’s hard to argue that that harm reduction is the outcome that we’re seeing,” Blagev said.

Is taking Juul off the shelves the right move?

In pulling Juul off the market, the FDA said Juul provided “insufficient and conflicting data” that precluded the agency from making a full assessment of the risks posed by chemicals in the device. Juul challenged the action in court, saying the FDA missed components of their application, and a federal appeals court has said the company can continue to sell its products while the court case proceeds.

The FDA’s cited reasoning surprised some experts. “Juul has the expertise, the scientific expertise, the legal expertise, and the money to put together a really blockbuster [application],” Warner said. “It’s hard for me to believe that they would have screwed up on something as bad as the toxicology issues the FDA is claiming.”

The exact problem with Juul’s application may never become clear. Experts who spoke to Grid differ on whether they thought removing Juul from the market struck the right balance between harm reduction and risk avoidance.

“It looks to me like the FDA disapproved Juul for the wrong reason. I agree with the disapproval, but not because of toxicology issues,” said Siegel. Juul’s capacity to deliver lots of nicotine quickly, coupled with its early marketing toward youth, “has really changed the nature of youth vaping, he said. “It’s a balancing act, and I think in the case of Juul, the risks just outweigh the benefits.”


Yet the same factors that make the addiction potential so high for youth also make the product more acceptable to smokers, Siegel said: “It’s a double-edged sword.”

Some worry taking a preferred smoking cessation tool off the market may lead to more smoking. “I’m very disappointed by it,” Warner said. While Juul clearly was a bad actor early on by marketing toward youth, when the FDA cracked down and forced the company to stop selling most flavored products, “they became much better citizens,” he said. Youth vaping has dramatically fallen since 2019, and now less than 6 percent of high school e-cigarette users regularly use Juul.

“There’s so many devices on the market, I don’t think removing Juul will make a big difference,” Benowitz said.

Striking the right balance between benefits and risk would have been much easier had e-cigarettes been more heavily regulated early on, Siegel said. “Instead of regulating the product to minimize the risks, they basically did nothing and let the market run rampant,” he said. Other countries, like the United Kingdom, have regulated e-cigarettes as a smoking cessation tool largely from the start, restricting youth advertising and limiting nicotine levels, and see much lower youth vaping levels.

“Had the FDA regulated [e-cigarettes] from the beginning, it clearly would have prevented the disaster that occurred,” Siegel said.

Thanks to Lillian Barkley for copy editing this article.

  • Jonathan Lambert
    Jonathan Lambert

    Public Health Reporter

    Jonathan Lambert is a public health reporter for Grid focused on how science, policy and the environment shape our collective well-being.