The largest and most up-to-date review of clinical trials on e-cigarettes has found high-certainty evidence that nicotine vapes help more smokers quit than standard nicotine replacement therapy, such as patches and gum. The update to the Cochrane Database of Systematic Reviews' living review on electronic cigarettes for smoking cessation pooled 80 randomized controlled trials covering nearly 30,000 participants, including nine studies added since the previous update.
The numbers
Compared with nicotine replacement therapy, nicotine e-cigarettes produced about four additional successful quitters for every 100 people who tried — a comparison the authors, led by Nicola Lindson of the University of Oxford, rated as high-certainty evidence. Against non-nicotine e-cigarettes, nicotine vapes produced roughly two additional quitters per 100. E-cigarettes also outperformed no support or standard behavioral support, such as counseling and group programs, though the authors had less confidence in that comparison because of possible bias in how some of the underlying trials were designed. The review reported no evidence that using e-cigarettes to quit smoking increased the risk of serious harm, while cautioning that data on long-term safety remain limited.
"Although nicotine vapes are unlikely to be completely risk free, they are less harmful than smoking," Lindson said. Senior author Jamie Hartmann-Boyce of the University of Massachusetts Amherst said there is now, for the first time, "very strong evidence that regulated nicotine e-cigarettes are substantially less harmful than smoking."
Caveats and reaction
The authors limited their conclusions to regulated, nicotine-containing e-cigarettes, not the unlicensed devices that make up a significant share of the market. Hartmann-Boyce warned that products failing to meet regulatory standards carry their own risks, including unstable batteries and unpredictable chemical exposure, and urged people trying to quit to use only devices approved by their country's regulator.
Reaction in the United Kingdom, where the review drew wide coverage, was broadly supportive but cautious. Caroline Cerny of Action on Smoking and Health said the findings confirm vapes are a highly effective quitting aid, while noting a recent ASH survey found 54% of UK adults still believe vaping is as harmful as, or more harmful than, smoking — a perception the review's authors say the evidence does not support for regulated products. Darush Attar-Zadeh of the Primary Care Respiratory Society said the results align with national treatment guidance that already lists nicotine vapes among the more effective quitting aids, alongside combination nicotine replacement therapy, cytisine and varenicline, but cautioned that the review does not show vaping beats optimized combination NRT specifically. A hospital pharmacist, Ravijyot Saggu of Chelsea and Westminster Hospital, raised a separate concern: that many vapes "aren't properly regulated," which she said poses risks especially in making them appealing to children and people who have never smoked.
Cochrane's tobacco addiction group plans to keep updating the review as new trials are published, and researchers noted a separate review is underway on how to help people quit vaping itself — an acknowledgment that for some users, nicotine vapes are better understood as a step away from cigarettes than as a risk-free destination.
