The results of a yearlong study published Wednesday in the New England Journal of Medicine ended with people who used e-cigs as a quitting aid to be twice as likely to stop smoking traditional cigarettes than those who used nicotine gum or patches. Study subjects were randomly assigned either electronic e-cigarettes or traditional smoking cessation treatments.

A bit of counseling was key, too. “E-cigarettes were more effective for smoking cessation than nicotine-replacement therapy, when both products were accompanied by behavioral support,” the study authors wrote.

Smoking costs the global economy nearly $1 trillion a year, and tobacco is responsible for millions of deaths worldwide every year.

One expert not involved with this particular research paper told the New York Times the study is “seminal” and “so important to the field.” Other public health experts wrote in the same issue of the Journal that they believed more research is needed to further validate the findings of this particular study, especially as e-cigarettes are not approved as a smoking cessation treatment by the U.S. Food and Drug Administration (FDA). Other researchers issued words of caution about flavored e-cigarettes, which many argue are marketed to teens who may end up starting a new habit instead of kicking an old one out of their lives.

Regardless of the existing research, several companies already bet big on e-cigs as a smoking cessation tool, including San Francisco-based Juul, which sold a 35% stake to Marlboro maker Altria in December in a deal worth $12.8 billion. While this latest study is new, Juul has already been planning a summer 2019 television advertising campaign that will feature former smokers.