The U.S. Preventive Services Task Force, an independent panel of experts that advises the government on public health issues, recently concluded that there's insufficient evidence to recommend e-cigarettes as a way to stop smoking conventional cigarettes. But when we reported on that news, we heard from more than 1,300 readers, most saying that electronic cigarettes helped them kick their habit.

Anthony Porcano, for example, told us in a Facebook comment that he was "smoke-free for over 12 months by using electronic cigarettes. They literally saved my life. Lung functions and all other aspects of my health have dramatically improved."

Smoking tobacco cigarettes still kills more than 480,000 Americans each year. And there's no doubt that quitting yields almost immediate health dividends, slashing your risk of heart attack, stroke, and lung cancer.

But e-cigs raise worrisome health concerns of their own. Some research has found harmful chemicals in e-cig vapor, including formaldehyde, which has been linked to nose and eye irritation and an increased risk of asthma and cancer. For example, researchers at the Center for Environmental Health, a nonprofit organization based in Oakland, Calif., recently tested 97 e-cig products and found formaldehyde, the chemical acetaldehyde, or both in more than half of them.

It's worth remembering that conventional cigarettes were once marketed as safe—and even good for you—by some of the same tobacco companies that are now producing e-cigarettes.

Other readers told us that e-cigs helped them quit after other methods failed: "I tried [nicotine] gum, patches, and pills. None of those worked. At the suggestion of a friend, I tried vaping. I started with disposables and now use an EVOD," Lisa Marie wrote in her Facebook message, referring to a refillable type of e-cigarette. "I have been tobacco-free for a year now!" Lisa Marie writes.

Reader James Nelson recounted a similar experience in his Facebook comment, telling us, "I attempted to quit using traditional FDA approved methods (patches, lozenges, etc). None of these methods worked for me." Nelson writes that he's "been cigarette free for over a year," but still uses a vaping device with nicotine-containing liquid.

While personal stories detailing the successful use of e-cigs as a smoking cessation tool are compelling, medical experts still look for evidence from randomized clinical trials—the gold standard in medical research—as proof that vaping can help tobacco smokers quit. The U.S. Preventive Services Task Force says in its report that it was only able to find two such trials done to date and neither showed that e-cigs are more effective than other smoking-cessation methods, such as nicotine patches.

Also worrying, many people who use e-cigarettes aren't trying to give up conventional cigarettes, but are actually new users—particularly adolescents. For example, the Centers for Disease Control and Prevention estimates that more than 263,000 middle and high school students who had never smoked before used e-cigs in 2013. And some research suggests that people who start using e-cigarettes are more likely to smoke tobacco cigarettes. That could be because nicotine itself is addictive.

Addressing that concern, Tom Frieden, M.D., director of the CDC, recently said, "Nicotine is not safe for the developing brain, and we must do everything we can to protect kids from a lifetime of tobacco use and nicotine dependence."

Finally, the liquid nicotine used to refill e-cigarette devices can be harmful. In 2014 the American Association of Poison Control Centers received 3,783 reports of nicotine exposures—half related to children under the age of five. On September 29, the Attorneys General of 33 states signed a letter urging the Food and Drug Administration to require e-cig liquid to be sold in tamper-resistant packaging and to carry warning labels. The letter also urged the FDA to "step up and regulate the sale and packaging of these dangerous products before any more kids are harmed."

For those reasons, while we acknowledge responses from readers describing their personal experiences, Consumer Reports recommends that people who smoke conventional cigarettes ask their doctors to recommend a counselor who specializes in smoking cessation to help them choose safe and effective methods for kicking the habit. And we think that other people, especially teens, should think twice before trying e-cigarettes.