By June 2018, a New York teenager’s addiction to Juul had become so intense that his parents took the door off his room, switched him to a different school, and asked that he be followed to the bathroom — all in an effort to prevent him from juuling. “He couldn’t stop, and so as a result, he’s not really having a normal teenage life at the moment,” says Jason Solotaroff, an attorney at Giskan, Solotaroff, and Anderson LLP who is representing the family.

The complaint, filed by the teenager’s mother, is just one of a trio of lawsuits unearthed by Wired reporter Nitasha Tiku. There’s also a class action suit with 10 named plaintiffs from across the country — some as young as 14 years old. “It’s accusing the company of making misleading representations about the nicotine exposure the product creates and the related risks of abuse and addiction that arise from those,” says Esfand Nafisi, an attorney at Migliaccio & Rathod LLP who is representing the plaintiffs in all three suits.

How bad is nicotine, really?

In an emailed statement, Juul took exception to the idea it marketed to teens but did not address the claims that it caused addiction. “Juul Labs does not believe the cases have merit and will be defending them vigorously,” company spokesperson Victoria Davis told The Verge. “We cannot be more emphatic on this point: no minor or non-nicotine user should ever try Juul. Our packaging includes a prominent nicotine label and clearly states that the product is for adult smokers.”

Marketing aside, the lawsuits raise the question: how bad is nicotine, really?

Law professor Kathleen Hoke, who specializes in public health law at the University of Maryland, says that in adults, nicotine’s health consequences “don’t kill you, don’t make you have an oxygen tank, don’t cause cancer.” Hoke adds that staking the lawsuits on nicotine’s health impacts — like in a traditional cigarette suit — may be a long shot. “That’s not going to be the nature of a winning case against Juul or other manufacturers of e-cigarettes, because the health consequences are not as severe,” she says — at least, in adults. Going after the company’s marketing and design strategies could be more successful, Hoke says.

Still, that doesn’t mean nicotine is harmless — particularly not for young people whose brains are still developing. Nicotine may also be risky to use while pregnant, the surgeon general reports. And when it comes to heart health, the jury’s still out; the risks of nicotine on its own “are low compared to cigarette smoking, but are still of concern in people with cardiovascular disease,” according to a 2016 review of the research published in the journal Trends in Cardiovascular Medicine. And there’s still a lot we don’t know about the long-term safety.

There’s still a lot we don’t know about the long-term safety

What’s more, nicotine is addictive. “We want to be really careful that we don’t demonize less harmful forms of nicotine, especially for anybody who’s going to be smoking anyway,” says David Abrams, a professor of behavioral and social science at New York University. “But we also want to make sure people know that it’s dependence producing.” That’s why he says no one under 21 years old should use any form of nicotine.

Compared to smoking cigarettes, which kills 6 million people around the world every year, nicotine on its own is less harmful. “If all you did when you inhaled cigarette smoke was just inhale nicotine, we wouldn’t see the kinds of health risks, and health harms, and burdens that we see,” says Nancy Rigotti, director of the Tobacco Research and Treatment Center at Massachusetts General Hospital. Cigarette smoke is a grab bag of chemicals — including 250 that are well-known to be bad for us, according to the National Cancer Institute. That includes heavy metals, carbon monoxide, and hydrogen cyanide. So when it comes to causing chronic lung disease or cancer, “we don’t think nicotine is a big player,” Rigotti says.

That’s why the Food and Drug Administration has approved nicotine replacement therapies like gum, lozenges, and patches. To be clear though, that list doesn’t include vapes, which are still largely unregulated and haven’t yet been convincingly shown to help people quit, according to the National Academies of Sciences, Engineering, and Medicine.

The science around nicotine and heart problems is a little murkier. About 40 percent of the deaths related to smoking are from cardiovascular disease, the National Institute on Drug Abuse reports. Though nicotine can make your heart race and temporarily boost blood pressure, it’s the non-nicotine components of tobacco smoke that are thought to damage and harden blood vessels, says Holly Middlekauff, a cardiologist at the Ronald Reagan UCLA Medical Center. “Nicotine itself hasn’t been largely studied compared to nothing,” she says. “We better be darned sure that it’s not the nicotine that’s triggering heart attacks — and that I don’t know.”

“Nicotine itself hasn’t been largely studied compared to nothing.”

Her lab is trying to find out by analyzing the electrical activity of people’s hearts after they puff on an e-cigarette with nicotine, an e-cigarette without nicotine, or an empty vape. The researchers were looking for a pattern of heart rate variability that’s been linked with cardiovascular events like heart attacks and sudden death. And they saw that pattern emerge only when the study participants vaped the e-cigarettes with nicotine, according to a paper published in the Journal of the American Heart Association in 2017. The study was small — just 33 people. And it was looking at a marker of heart problems, not at the heart problems themselves. So we still need big, long-term studies that compare the frequency of heart attacks among vapers to smokers and non-smokers.

Studies of people who use snus — a smokeless tobacco popular in Europe — offer some insight into the effects of nicotine minus the smoke produced by burning tobacco and the chemicals it’s laced with. “In that population, there’s no evidence of accelerated atherosclerosis or higher risk of heart attacks,” says Neal Benowitz, who studies the pharmacology of nicotine at the University of California, San Francisco. But those who continued to use snus after a heart attack were more likely to die over the next few years, according to a study of more than 2,000 snus users published in the journal Circulation in 2014.

So nicotine may be risky for people with existing heart problems. But, Benowitz says, using “nicotine to quit smoking is less hazardous than smoking.” (Benowitz has consulted for pharmaceutical companies about smoking cessation medications, and is not funded by any tobacco or e-cigarette companies. “I did have one small grant from a tobacco company, but that was 35 years ago,” he says. “When I figured out what was going on, that was the end of that.”)

The surgeon general warns that nicotine use during pregnancy might also be harmful to fetal brain development and increase the risk of preterm delivery and stillbirth. “If you’re pregnant, taking nicotine is not a good idea — however, if you’re a smoker, that’s much worse,” Benowitz says. So if people need nicotine replacement to quit smoking while pregnant, he says, “It’s a good trade-off.”

Addiction is a distressing health outcome

There’s one adverse health effect that nicotine is clearly, unequivocally responsible for, and that’s addiction. There’s a quote that’s been bouncing around the tobacco research community since the 1970s, that “people smoke for nicotine but they die from the tar.” But the addiction, “in and of itself, is a distressing health outcome,” says Adam Leventhal, a clinical psychologist and a professor of preventive medicine at the University of Southern California. People who are addicted to nicotine “can feel that their behavior is restricted by their intense urge and cravings to use the drug,” he says.

It’s an argument made by the New York lawsuit, filed by the mother of a teenage Juuler known only as D.P. The complaint alleges that D.P. can stop Juuling only for short periods of time, before “what he refers to as ‘urges’ return and become so powerful that he is unable to avoid Juuling even though it subjects him to disciplinary measures at home and at school.”

For young people, the risk of getting hooked is thought to be even greater than for adults, the National Academies of Sciences, Engineering, and Medicine report. Almost 90 percent of smokers took their first puff by age 18, according to the Centers for Disease Control and Prevention. Studies in rats suggest that nicotine hits adolescent animals harder: young female rats that could press a lever to deliver nicotine directly into their bloodstreams took more hits of the stuff than adult rats did. And adolescent rats given nicotine also showed more signs of activity in regions of the brain related to feelings of reward than adult rats did, a 2009 literature review reports in the journal Pharmacological Therapy.

“Nicotine is one of the most addictive substances available in a consumer product.”

Of course, caffeine’s addictive, too — and there isn’t a moral panic about teens drinking coffee. But Leventhal says comparing the two drugs is like comparing apples and oranges. “We know that nicotine is one of the most addictive substances available in a consumer product,” he says. And withdrawing from nicotine is awful: “Anxiety, depression, irritability, hunger, weight gain — all of those are symptoms of nicotine withdrawal, which are unpleasant. So that sums it up,” Leventhal says. Hoke asks: “Why introduce an addiction into your life that is going to deprive you of choice?”

That’s why when I asked Rigotti how bad nicotine is, she suggests the answer is relative. It’s better to use nicotine by itself than to smoke cigarettes — which is where vapes could play a part, if they wind up helping smokers quit. “We need to find out,” Rigotti says. “But there’s no benefit for young people, or anybody who’s not already nicotine-addicted.”

Benowitz agrees, but says that the same things that make the device attractive for smokers also raise concerns about non-smokers getting hooked. “Juul has to figure out how to keep it out of the hands of kids, and make it available for smokers,” he says. The company says they’re “working tirelessly” to do so — and Benowitz thinks that the stakes are high: “Otherwise, the product’s not going to survive.”