Pooled data from eleven trials found nicotine e-cigarettes produced higher quit rates than nicotine replacement therapy at six months or longer (risk ratio 1.61, 95% CI 1.23 to 2.12; 4,114 participants), evidence Cochrane rates as high certainty, its top tier of confidence. In absolute terms, the review’s authors translate this to roughly one to seven additional quitters per 100 people using nicotine e-cigarettes instead of NRT.

Two further comparisons reinforce the same direction of effect. Against non-nicotine e-cigarettes, nicotine e-cigarettes probably increased quit rates (risk ratio 1.34, 95% CI 1.05 to 1.69; moderate-certainty evidence, 1,918 participants), isolating nicotine’s own contribution. Against behavioral support alone or no support, nicotine e-cigarettes showed a larger effect (risk ratio 1.75, 95% CI 1.39 to 2.20; 7,214 participants), though this comparison is rated only low certainty because none of the contributing trials could be blinded.

Across the three main comparisons, the review found no clear increase in serious adverse events for nicotine e-cigarette users. Against NRT, serious adverse event rates were similar (risk difference 0.01, 95% CI -0.01 to 0.02; moderate-certainty evidence, 4,045 participants), and many contributing studies recorded zero serious events in either arm. Against non-nicotine e-cigarettes, the picture was the same (risk difference 0.00, 95% CI -0.01 to 0.01; low-certainty evidence).

Non-serious adverse events told a more mixed story. Compared with NRT, rates were similar but the certainty was downgraded this update, from moderate to low, because inconsistency between trials increased. Compared with behavioral support or no support, the review’s authors estimate roughly nine additional people per 100 assigned to nicotine e-cigarettes may experience a non-serious adverse event, evidence rated very low certainty due to both risk of bias and imprecision. None of this pattern points to serious short-term harm, but the authors are candid that longer-term safety data beyond two years remain limited.

The reviewers built a scope limitation directly into their protocol: because nicotine is what drives tobacco dependence, the review evaluates only nicotine-delivery vaping devices and does not extend to vaping devices used for cannabis or other substances. That is a deliberate methodological choice, not an oversight, and it means none of this review’s quit-rate or safety findings can be responsibly generalized to THC vape cartridges or other cannabis vaporizer products.

The distinction has real clinical stakes. The 2019 to 2020 outbreak of severe vaping-associated lung injury in the United States, which the CDC and FDA eventually named EVALI and which involved roughly 2,800 hospitalizations and 68 deaths by February 2020, was ultimately traced to illicit THC-containing vape products adulterated with vitamin E acetate, not to regulated nicotine e-cigarettes. Patients who ask whether ‘vaping is safer’ are often unaware that the product category driving that outbreak was cannabis vape cartridges, and this review’s favorable nicotine-cessation findings say nothing about the safety of that separate product category.

Of the 80 included trials, the review’s authors rated 12 at low overall risk of bias, 27 at unclear risk, and 41 at high risk, with most of the high-risk ratings concentrated in the behavioral-support comparison, where blinding is not possible by design. Of 75 studies that reported funding sources, 8 disclosed tobacco or vaping industry support. The authors ran sensitivity analyses removing every industry-funded and every high-risk-of-bias study from each pooled comparison; in every case, the direction and interpretation of the results held.

That transparency is part of why this review carries weight. It does not paper over its own limitations. It flags that most included trials came from the United States and United Kingdom, that funnel plots for several outcomes showed some asymmetry (interpreted cautiously given fewer than a dozen contributing studies each), and that rapid changes in e-cigarette device technology mean there is always some lag between the devices tested in older trials and what is currently sold.

This update sits inside a decade-plus effort by the Cochrane Tobacco Addiction Group to keep pace with a product category that keeps changing, from early ‘cig-a-like’ devices with poor nicotine delivery, to refillable tank systems, to today’s nicotine-salt pod and disposable devices. The review’s authors note that newer devices generally deliver nicotine more efficiently, which is part of why the certainty of the cessation evidence has strengthened across successive updates rather than weakened.

The EVALI outbreak remains the clearest real-world illustration of why product category matters more than the word ‘vaping’ alone. Regulatory bodies, including the FDA, eventually confirmed the outbreak was concentrated in illicit THC-containing cartridges cut with vitamin E acetate, a thickening agent never used in nicotine e-cigarette liquids. That episode reshaped public perception of vaping risk generally, even though the underlying products were pharmacologically and legally distinct from the nicotine devices this Cochrane review evaluates.

What I find most clinically useful about this update is not just that the cessation evidence has gotten stronger, it is that the review’s authors were disciplined enough to draw a hard line around what nicotine vaping evidence can and cannot tell us. Too much of the public conversation about vaping treats it as a single category, when in practice the regulated nicotine e-cigarette market and the largely unregulated THC vape cartridge market are governed by different manufacturing standards, different additives, and, as EVALI showed, different failure modes entirely.

For patients who smoke tobacco and also use cannabis, and there are many in this practice, I read this review as genuinely useful, high-certainty support for offering nicotine e-cigarettes as a smoking-cessation option where appropriate and legal, alongside honest counseling that this evidence says nothing about the safety of THC vape cartridges. Those are two separate clinical conversations, and conflating them does patients a disservice in either direction.

Four distinctions worth keeping straight