Existing research showed that cessation of smoking for more than six months after using nicotine-containing e-cigarettes compared with using nicotine replacement therapy (3 studies; 1498 people) or nicotine-free e-cigarettes (3 studies; 802 people) There may be more.

Nicotine-containing e-cigarettes may be more helpful for smoking cessation than no support or behavioral support alone (4 studies; 2312 people).

10 out of 100 smokers who use nicotine-containing e-cigarettes to quit are likely to be successful. This compares to 6 out of 100 smokers who use nicotine replacement therapy or nicotine-free e-cigarettes. For people with no or only behavioral support, only 4 per 100 people successfully quit.

We are uncertain whether there is a difference in adverse effects between the use of nicotine-containing e-cigarettes and nicotine-free e-cigarettes, nicotine replacement therapy, no support, or only behavioral support. The number of adverse effects, including serious adverse effects, reported for all measures in the available studies was low.

The most commonly reported adverse effects of nicotine-containing e-cigarettes are sore throat or mouth, headache, cough and nausea. These adverse effects gradually subsided as subjects used nicotine-containing e-cigarettes for longer.

How reliable are these findings?

The number of studies from which the results come from is small, and the data for some indicators vary widely.

We have moderate confidence that nicotine-containing e-cigarettes help more people quit smoking than nicotine replacement therapy or nicotine-free e-cigarettes. However, these results may change if more evidence emerges.

We are uncertain about how nicotine-containing e-cigarettes compare with smoking cessation outcomes without support or behavioral support.

When more evidence becomes available, adverse effects-related outcomes may change.

Key Information

Nicotine-containing e-cigarettes may indeed help smokers quit smoking for more than half a year. Nicotine-containing e-cigarettes may work better than nicotine replacement therapy and nicotine-free e-cigarettes.

Nicotine-containing e-cigarettes may be more effective than no support or behavioral support alone, and may not have serious adverse effects.

We still need more reliable evidence for the effects of e-cigarettes, especially newer ones with better nicotine release.