At a vaping bar beneath neon lights, fingers tap on the wooden counter. A vial of "vape juice" pours into a pen-shaped device. With the click of a button, electricity flows, a coil heats, and flavored, diluted, liquid nicotine transforms to a gas. It's inhaled and exhaled in a vanilla custard nimbus that hovers in the Henley Vaporium in Manhattan that sells all manner of e-cigarette devices, vape pens, and "mods" for delivering vaporized nicotine into users' lungs and bloodstreams.

"I'm sure this isn't good, but it's a lot better than cigarettes," said Patrick A., a 38- year old commodities options trader who asked only to be identified by his first name. Those like him switching from cigarettes, and new users, are contributing to the growth of the estimated $2 billion e-cigarette industry.

Indeed, according to a study in the peer-reviewed journal Addiction, vaping is 60 percent more effective for quitting cigarettes than nicotine patches, gum, or going cold turkey. But just because e-cigarettes are tar-free doesn't mean they're risk-free.

A "mod," or modified e-cig, sits on the bar at Henley Vaporium in New York City. Jim Seida / NBC News

There are no studies on its long-term effects of e-cigs because they're a relatively recent development. And e-cigarette manufacturers have been criticized for targeting the young and using television advertising, which traditional cigarette companies have been banned from doing since 1970.

All that aside, vapers aren't waiting for science or the government to tell them what they know in their lungs to be true, and what they come to vaping lounges to have reconfirmed.

"We know cigarettes kill you. And we know what in cigarettes kill you. And we know that vaping does not contain the things in cigarettes that kill you," said Peter Denholtz, co-owner of the Henley Vaporium.

Lest they forget, a fraction of the chemicals in a lit cigarette are stenciled on his shop's wall in thick black letters. Arsenic. Cobalt. Lead. 2-Nitropropan. 5-Methyl-Chrysene.

"We know cigarettes kill you. And we know what in cigarettes kill you. And we know that vaping does not contain the things in cigarettes that kill you."

Each time the vapers cross the store's threshold they do so renouncing these thousands of chemicals in exchange for just five FDA-certified ingredients: water, food flavoring, propylene glycol, glycerin and nicotine.

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Especially the last one. Because most are still addicts. Though in bursts of rapid shop talk users say at least now they're not consuming tar and 68 other carcinogens to feed their need. Or digging through garbage for old butts to burn when they bolt up from sleep in the middle of the night, out of cigarettes, and out of their minds for a fix.

That used to be Jordy Tractenberg, a 45-year-old music rights negotiator. Four weeks after trading his two-pack a day habit for a vape pen, he says he took a hot shower. As the steam entered his nostrils, he began coughing and filled the drain with "lung cookies," heavy, green and black chunks of mucus. Vaping was giving his respiratory system a chance to start working through a 30-year backlog, he said.

"All of a sudden, you can breathe," he said.

Vapoligist Tristan Ambat, left, explains to customer Lee Coats that his modified e-cig, or "mod," needs a rebuild, at the Henley Vaporium in New York City. "I'm only four months into this," said coats, referring to inhaling electronic cigarettes, "It involves a lot of maintenance where you have to make your own wick out of organic cotton. I didn't twist the wick correctly and it created a bad taste." Ambat performed the rebuild in a few minutes and it cost Coats $5. Jim Seida / NBC News

The medical community allows that nicotine on its own is a relatively harmless, though addictive, stimulant.

"You remove the combustion process and you obviously have a safer product," said Dr. Taylor Hays, director of the Mayo Clinic Nicotine Dependence Center. "It would be impossible to assume they're safe given that the industry is completely unregulated and given that people are inhaling different chemicals deep into their lungs."

But for Tractenberg that's a gamble he's willing to take. Key to helping him stay clear of cigarettes are the vape shops, he said. Many of the shops and lounges were started by impassioned ex-smokers who wanted to help others like them switch to e-cigarettes, and build a business at the same time. Tractenberg frequents Beyond Vape on St. Mark's Place in New York to sample the new flavors and to commune with the vaping faithful.

"It's kind of like what a cigar shop would have been back in the day. Or an old school barber shop," said Tractenberg. "People talk about flavors and devices, sports, politics, sex, drugs and rock and roll."

Lee Coats, an e-cigarette user, exhales vapor at Henley Vaporium in New York City. Jim Seida

Not every customer goes for the gab-fest. "I go in and buy my juice and leave, I'm good," said Caren Evans, a 54-year-old public relations executive in Maryland.

Like others, Evans leans on the vape shops to help her step down the amount of nicotine she's inhaling. It's both to have more power over her addiction and because nicotine's bitterness drowns out the e-liquid flavors.

Most users getting away from cigarettes start off on 24 mg nicotine strength juice. Evans had worked her way down to 12mg. One day she was in Vape Ink in Rockville, Maryland, for a refill and they didn't have her favorite, a strawberry custard flavor called Unicorn Milk, available in that dosage, only 18 mg.

Because of her pride in getting down to 12 mg, the store strongly advised her not to buy it, she said. "The guy looks at me, and said if you're at 12, I'm not selling you 18. That would be wrong." These days she's down to 6 mg.

"The shops and the e-cigarette companies want to have it both ways. They say they're out there trying to help smokers quit, but they also want to get new users."

But there's more to the revenue stream for vape shops than just getting smokers off cigarettes.

"The shops and the e-cigarette companies want to have it both ways. They say they're out there trying to help smokers quit, but they also want to get new users," said Thomas Fairely, a former NYC health commissioner.

Blu and NJOY, two of the biggest brands of e-cigarettes, and the types that most vape users try first before graduating to the customizable and refillable types sold at vape shops, have aggressive marketing campaigns. Actors and actresses were seen puffing away on e-cigs at tables during the Golden Globes. NJOY hired hunky young men wearing nothing but swim shorts to pass out free samples on-board New York City subway cars.

"That's not how you market to smokers. That's how you market to teenage girls," said Fairely. "They're treating this like any other product where the bigger the market, the better."

"The best way is not going after smokers, but non-smokers."