It is common knowledge that one of the most unhealthy things you can do is smoke. Cigarette smoking takes an average of 10 years off a person’s life due to lung cancer and other lung diseases, as well as deaths from heart attack and stroke.

So when e-cigarettes were developed in 2003, they were seen as healthier than conventional cigarettes, even though there was no proof that this was the case.

Still, because of that perception, the e-cigarette industry has blossomed into a multibillion-dollar business, according to the World Health Organization.

An e-cigarette contains a cartridge of fluid that is made up of nicotine and various flavorings. This fluid is superheated, converting into a vapor that is inhaled, or “vaped.”

E-cigarettes do not contain hundreds of other toxic chemicals found in conventional cigarettes, but they do contain nicotine. And although e-cigarettes escaped scientific scrutiny in their early years, they are now under the jurisdiction of the U.S. Food and Drug Administration, and research results are starting come in.

For instance, a University of California, San Francisco, study published in August 2018 looked at an analysis of nearly 70,000 people and found that daily use of e-cigarettes doubled heart attack risk.

Not only that, but daily use of both e-cigarettes and conventional cigarettes — which is how many people use them — hiked heart attack risk fivefold. So when it comes to smoking, the safest thing you can do is quit.

Talk to your doctor about the best methods, including medication. But don’t be fooled into thinking that e-cigarettes are a safe way to quit.