Ask a London smoker whether vaping is safer than smoking and most will say "probably" without being able to say by how much, or why. That gap between a hunch and the evidence matters, because the answer shapes real decisions — whether to try an e-cigarette instead of another pack of cigarettes, whether a GP recommends it, and how London’s stop smoking services are funded and run. The evidence base on vaping vs smoking is now large enough to be specific rather than vague, and specific is what this piece aims to be.
The size of the risk difference
The starting point, echoed across UK public health guidance, is that vaping is not risk-free but is substantially less harmful than smoking. The Office for Health Improvement and Disparities (OHID, the successor body to Public Health England) has put a figure on this: e-cigarettes are estimated to be around 95% less harmful than smoking tobacco cigarettes. A 2022 evidence review by UK experts reached a similar conclusion, finding that in the short and medium term vaping poses only a small fraction of the risks of smoking.
The mechanism behind that gap is straightforward. Cigarettes work by burning tobacco, and combustion is what produces tar and carbon monoxide — two of the most damaging components of cigarette smoke, and major drivers of the cancer, lung disease, and cardiovascular risk associated with smoking. E-cigarettes heat a liquid rather than burning plant material, so users are exposed to far fewer toxins, and at lower levels, than someone smoking tobacco. Studies of smokers who switch completely to vaping have found substantial reductions — often 90% or more — in biomarkers of exposure to tobacco-specific carcinogens, in some cases approaching the levels seen in people who use neither product.
How vaping compares with nicotine replacement therapy
Reducing harm is only half the picture; the other half is whether vaping actually helps people quit. Here the evidence is unusually strong for a public health question. A Cochrane review published in November 2022 rated the evidence as "high certainty" — the highest grade Cochrane assigns — that nicotine e-cigarettes are more effective for quitting smoking than traditional nicotine replacement therapy (NRT) products such as patches and gum. The review’s figures were specific: for every 100 people who used a nicotine e-cigarette to try to quit, roughly 8 to 12 were still not smoking six months later, compared with around 6 of every 100 using NRT alone.
A separate review found that people who combined e-cigarette use with expert face-to-face stop-smoking support could be up to twice as likely to succeed as those relying on other NRT products alone. Nicotine strength appears to matter here: e-cigarettes containing nicotine consistently outperform non-nicotine versions and no-intervention comparisons, because managing cravings effectively is central to why the method works at all.
| Method | Approximate quit success (per 100 users) | Evidence grade |
|---|---|---|
| Nicotine e-cigarette | 8–12 | High certainty (Cochrane, 2022) |
| Nicotine replacement therapy (patches, gum) | 6 | High certainty (Cochrane, 2022) |
| E-cigarette + face-to-face support | Up to 2x NRT-alone rates | Reviewed evidence, 2021 |
Why dual use undermines the benefit
One qualification is easy to miss. The harm-reduction case for vaping depends entirely on a smoker stopping cigarettes completely, not on adding vaping alongside them. People who continue smoking while also vaping — commonly called dual use — do not get the same health advantage as someone who switches fully, and some evidence suggests dual users can end up with toxic exposure levels similar to those who smoke exclusively. For anyone considering vaping as a route off cigarettes, the evidence points toward treating it as a full swap rather than a supplement.
What London and national policy have done with this evidence
The evidence above is not abstract; it has shaped concrete national policy that Londoners encounter directly. The "Swap to Stop" scheme, launched in 2023, is a national initiative aiming to help around a million smokers in England switch to vaping, with roughly one in five smokers offered a free vape starter kit alongside behavioural support. It sits within a wider government target of bringing smoking prevalence in England below 5% by 2030, and includes financial incentives to encourage pregnant smokers to quit.
At the same time, regulation has tightened around vaping itself, reflecting the "not risk-free, not for everyone" part of the evidence. The sale and supply of single-use disposable vapes was banned in the UK from 1 June 2025, driven partly by concern about underage use and environmental waste from discarded devices; reusable vapes remain legal. A Vaping Products Duty is due to apply to all vaping liquids sold in the UK from October 2026, intended to raise prices and further restrict access, particularly for minors. Underlying product safety continues to sit under the Tobacco and Related Products Regulations 2017, which set an 18+ purchase age, caps e-liquid bottles at 10ml and tank capacity at 2ml, limits nicotine concentration to 20mg/ml, and requires child-resistant, health-warning packaging.
Reading the evidence as a whole
Put together, the picture is more precise than the everyday shorthand of "vaping is better than smoking." It is: vaping carries a small fraction of smoking’s risk, outperforms standard nicotine replacement therapy for quitting when used as a full substitute, and is being deliberately built into national quit-smoking policy — while regulators simultaneously restrict the products most associated with underage and non-smoker uptake. For anyone in London weighing up their own next step, or trying to make sense of why the guidance sounds like both an endorsement and a caution at once, that combination is not a contradiction. It is what the evidence, read in full, actually says.