Ask Dr. K: Safety of e-cigarettes has yet to be proved

The truth is that nobody knows if e-cigarettes are safe. That’s because e-cigarette makers have not submitted their products for FDA approval, which would require proof of safety and effectiveness. Ads claim e-cigarettes help people stop smoking, but I’m not aware of any strong evidence to back this up.

For readers who’ve never seen one, e-cigarettes look like regular cigarettes or cigars. Others look more like pens. They all are built around a battery-operated heating element, a cartridge that contains nicotine and other chemicals, and an atomizer that converts the chemicals into an inhalable vapor. E-cigarettes vaporize a solution of nicotine dissolved in water and propylene glycol. That’s a fluid that helps nicotine dissolve.

Why would anyone smoke an e-cigarette? Regular cigarettes contain nicotine — the substance that smokers become addicted to. They also contain tars that can cause cancer. Proponents say that an e-cigarette gives a person the feeling of smoking without the risks.

E-cigarette smokers inhale nicotine, water and propylene glycol. The nicotine stems the craving that drives some ex-smokers back to regular cigarettes. But e-cigarette smokers don’t inhale tar, carbon monoxide, or the thousands of other substances in tobacco smoke. So while an e-cigarette smoker does remain with a nicotine addiction, he or she doesn’t have to worry about getting cancer.

Or so the proponents of e-cigarettes say.

But don’t be fooled. There are still many reasons to worry about e-cigarettes. First, the dose of nicotine delivered with each puff may vary substantially. Nicotine is a stimulant and very high levels can irritate heart rhythm. Granted, there is no strong evidence that e-cigarettes can cause dangerous heart rhythms — but that is because there are no large, high-quality studies of the safety of e-cigarettes.

Second, e-cigarettes still contain an array of chemicals. These include diethylene glycol, a highly toxic substance; formaldehyde, a powerful carcinogen; and at least four other chemicals suspected of being harmful to humans. There is no proof that e-cigarettes increase the risk of cancer the way real cigarettes surely do, but again, that’s because there are no good, long-term studies of safety.

Third, e-cigarettes are designed to simulate the smoking experience. By doing so, they might tempt ex-smokers into resuming the habit. They could also be a gateway into cigarette smoking for young people who are not yet hooked. Until we have scientific studies, it’s buyer beware.

If you’re an ex-smoker on the brink of relapse, consider the many well-studied, FDA-approved nicotine replacement products on the market. These include patches, gums, lozenges, inhalers and nasal sprays. They are vastly preferable to smoking. And, until we have more studies, to electronic cigarettes.

Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.