New Eng. J. Med. https://doi.org/10.1056/NEJMoa1808779 (2019)

In a randomized trial of smoking cessation, individuals that received an E-cigarette to use were more likely to cease smoking than those that used nicotine products designed to help quit smoking.

It is largely unknown how useful E-cigarettes are for quitting smoking in comparison with other nicotine products.

Researchers from the United Kingdom recruited 886 individuals who were seeking help to quit smoking from stop-smoking clinics. All participants received counseling in addition to either refillable second-generation E-cigarettes or nicotine replacement. After a year, those who had received an E-cigarette in addition to counseling were more likely to have abstained from smoking than those in the other group.