Kim Painter

Special for USA TODAY

A year ago, Ryan Standifird, 26, of Tustin, Calif., was a pack-a-day smoker who wanted to quit. He had tried and failed before.

Then, as part of a magazine writing assignment, he tried e-cigarettes. The battery-powered devices heat up flavored liquids, creating vapors that users inhale. Most contain nicotine, the chemical that makes regular cigarettes so addictive. With free supplies from a friend’s “vape” shop, Standifird says he easily made the switch. Aside from one two-month slide back to smoking, he’s been a vaper (an e-cigarette user) ever since.

“It’s the closest thing I’ve found to replicating smoking a cigarette. The amount of vapor is pretty much the same … the feel of it in my hand, the tobacco flavor, the nicotine hit,” Standifird says. “There’s also the social aspect. I still have friends who smoke, and it’s nice to be able to go out with them and puff on my e-cigarette.”

So is Standifird’s experience a quitting success story — or a cautionary tale about trading one unhealthy addiction for another?

The answer is complicated, and a source of heated debate.

“What we have going on right now is a natural experiment,” says Thomas Glynn, a former official at the American Cancer Society, now a consulting professor at Stanford University’s school of medicine.

Unknown numbers of U.S. smokers are trying e-cigarettes as smoking cessation aids. No major medical group in the United States recommends the practice, but that could change.

Here are some of the questions fueling the debate.

Do e-cigarettes really help people quit?

“We have no definitive data,” Glynn says. But, he says, preliminary trials suggest “they are probably about as good,” as other nicotine replacement products, such as gums and patches.

Those studies were done with older e-cigarettes that delivered nicotine less effectively, says Christopher Bullen, a researcher at the University of Auckland in New Zealand. Newer products may work better, he says.

E-cigarettes will never be “a silver bullet,” he says, but could be “a lifeline for many people who have struggled to stop smoking before and failed time and again.”

But Stanton Glantz, professor of medicine at the University of California-San Francisco, sees existing research differently. He is convinced, he says, that “for most people, (e-cigarettes) inhibit quitting,” creating dual users who vape and smoke.

Glantz says quitters should stick to proven methods, including counseling and medications approved by the Food and Drug Administration.

Those are the best choices right now and they are underused, says Edward Anselm, a New York City physician who advises insurance companies and is a senior fellow at the non-profit R Street Institute. But, Anselm says, doctors should cheer on any smoker eager to quit with e-cigarettes. “They’re motivated, they are ready and they have a plan,” he says.

How safe or unsafe are they?

In a recent survey, 35% of adult smokers said e-cigarettes were at least as harmful as conventional cigarettes, up from 12% in 2012.

That’s just wrong, says Cliff Douglas, vice president of tobacco control at the cancer society. “They don’t pose equal risk. Conventional combustible tobacco products are far more harmful.”

The Royal College of Physicians in the United Kingdom estimates that conventional cigarettes are 95% more dangerous than e-cigarettes.

“There’s no data to support that,” or any exact risk comparison, Douglas says. Still, he says, the cancer society is working on updated messaging to help the public better understand the available science.

An e-cigarette produces some toxins, he says, but nothing like the 7,000 chemicals, including 70 human carcinogens, produced by a lit tobacco cigarette.

What about nicotine? The nicotine in e-cigarettes is addictive and can raise blood pressure, “but nicotine is not a carcinogen,” Glynn says.

“The burned cigarette is public enemy No. 1,” he says. “That’s what is killing half a million Americans and 6 million people around the globe each year.”

Even Glantz, among the fiercest critics of e-cigarettes, says they are no doubt less toxic than conventional cigarettes. “If somebody switches entirely and is just using an e-cigarette, you are better off, but probably not as better off as you like to think.”

The FDA has just started regulating e-cigarettes. It says the devices have “both potential benefits and risks” and has banned their sale to minors.

What could go wrong in real-world use?

Among fears: e-cigarettes could renormalize smoking, create a pathway to smoking for young people and rob current smokers of a reason to quit by letting them vape where smoking is forbidden. Those are among the reasons many health advocates want e-cigarettes banned everywhere smoking is banned.

Another fear: Vapers who cut down but do not quit smoking may have an exaggerated view of the health payoff. Even a few cigarettes a day pose important health risks, Douglas says.

Finally, no one knows the long-term risks for ex-smokers such as Standifird who go on to vape for months or years. Ideally, they would wean themselves off their new habit as quickly as possible, Glynn says.

“I know I should quit,” Standifird says, because of the health risks and the costs (about $6 a day for his refill cartridges). “But I enjoy it. I enjoyed smoking and I enjoy vaping.”