Vaping vs smoking: which is worse for you? The evidence points clearly in one direction. For an adult who already smokes, switching completely to vaping cuts exposure to the chemicals that cause cancer, lung disease and heart disease by a large margin. But less harmful is not the same as harmless, the long-term effects of vaping are still unknown, and for anyone who does not smoke, vaping adds risk rather than removing it.
This guide sets out what the major reviews have found, from the US National Academies of Sciences, Engineering, and Medicine (NASEM), the UK government’s 2022 evidence update and the Cochrane review of vaping to quit. If you are ready to stop, our guide on how to quit smoking ranks every method by the strength of its evidence.
In this guide
Vaping vs smoking: the short answer
The 2022 evidence update published by the UK Office for Health Improvement and Disparities (OHID), led by researchers at King’s College London, reached four main conclusions:
- In the short and medium term, vaping poses a small fraction of the risks of smoking.
- Vaping is not risk-free, particularly for people who have never smoked.
- The evidence covers mostly short and medium term effects, and studies of vaping for longer than 12 months are needed.
- Better, more consistent study methods would make the evidence easier to interpret.
NASEM’s 2018 report, the largest US review, came to a similar view. It found that e-cigarettes are not without health risks but are likely to be far less harmful than combustible cigarettes, because their aerosol contains fewer toxic substances, at lower levels, than tobacco smoke.
Both reviews make the same comparison. Vaping is less harmful than smoking. It is more harmful than breathing clean air. Which of those comparisons applies to you depends on whether you smoke now.
| Question | What the evidence says |
|---|---|
| Vaping compared with smoking | Far lower exposure to cancer-causing and other toxic chemicals |
| Vaping compared with not using nicotine | Similar or higher exposure to harmful substances |
| Vaping to quit smoking | Helps more people quit than nicotine patches or gum (high-certainty evidence) |
| Long-term effects of vaping | Not yet known; most studies last 12 months or less |
| Vaping while still smoking | Little health benefit unless smoking stops completely |
Why smoking does so much damage
Most of the harm from cigarettes comes from burning tobacco. Smoke from a lit cigarette contains thousands of chemicals, including tar, carbon monoxide and dozens of known carcinogens. These are what drive lung cancer, COPD, heart attacks and strokes.
Nicotine is what makes cigarettes addictive, but it is not the main cause of smoking-related disease. Many smokers believe otherwise. In the OHID report, only 11% of adults who smoked knew that none or only a small amount of the risk of smoking comes from nicotine.
Vaping products heat a liquid, usually containing nicotine, flavourings, propylene glycol and glycerine, to make an aerosol. There is no burning tobacco, so there is no tar and no carbon monoxide from combustion. That single difference explains most of the vaping vs smoking gap.
Nicotine itself still has effects. It is addictive, and it raises heart rate and blood pressure in the short term. The OHID review found that one measure of artery stiffness, pulse wave velocity, did seem to be affected by nicotine from vaping, at least in studies of short-term use. If you are watching your blood pressure numbers, that is one reason to treat vaping as a step towards stopping nicotine altogether.
Vaping vs smoking: what the exposure studies show
Because vaping is relatively new, there are no 30-year studies of vapers to compare with smokers. Researchers instead measure biomarkers of exposure: levels of specific toxic chemicals, or their breakdown products, in the blood, urine or breath.
The OHID review pooled these studies. Compared with people who smoked, people who vaped had significantly lower levels of biomarkers linked to cancer, respiratory disease and cardiovascular disease. Some examples from its meta-analyses:
| Biomarker | What it tracks | Level in vapers compared with smokers |
|---|---|---|
| NNN | A tobacco-specific carcinogen | 90% lower |
| NNAL | A tobacco-specific carcinogen linked to lung cancer | 58% lower |
| 3-HPMA | Exposure to acrolein, a lung irritant | 71% lower |
| MHBMA | Exposure to 1,3-butadiene, a carcinogen | 83% lower |
| CNEMA | Exposure to acrylonitrile, a likely carcinogen | 94% lower |
The same review found the other side of the picture. Compared with people who used no nicotine products at all, people who vaped had similar or higher levels of harmful substances. That is why the authors encourage smokers to switch completely, while discouraging people who have never smoked from starting.
What we still do not know about vaping vs smoking
The biggest gap in the vaping vs smoking evidence is time. Smoking took decades to reveal its full damage, and vaping has not been widely used for long enough to show what 20 or 30 years of daily use does.
- Long-term disease risk. The OHID review could not summarise exposure beyond 12 months, and its authors call for longer studies.
- Heart and lung outcomes. Studies of biomarkers of harm gave only limited conclusions, although better-run short and medium term studies found no major causes for concern.
- Flavourings. There is little evidence on whether flavourings change the risk. The review singled out cinnamaldehyde, a cinnamon flavouring, as a cause for concern.
- Safety in trials. The Cochrane review found no clear evidence of harm from nicotine e-cigarettes, but its longest follow-up was two years and the number of studies was small.
In practice, this means vaping is a much better choice than smoking, but not a habit to keep for life if you can stop.
Where the “95% less harmful” figure came from
You will often see vaping described as “95% less harmful than smoking.” The figure became widely known after a 2015 report by Public Health England, but it traces back to a 2014 exercise in which a panel of experts scored the relative harms of different nicotine products.
That estimate has been criticised. The original authors noted a lack of hard evidence on the harms of most products, and an editorial in The Lancet called it a flimsy foundation for such a major conclusion. The 2022 OHID update, the most detailed review so far, does not rely on a single percentage. It uses the more cautious phrase “a small fraction of the risks of smoking.”
The direction of that claim is well supported. The exact number is not, so it is best not to quote it as a scientific finding.
EVALI and popcorn lung
Two health scares shaped public opinion on vaping, and both need context.
EVALI. In 2019 and early 2020, the US saw an outbreak of severe lung injury linked to vaping, known as EVALI. By February 2020, the CDC had recorded 2,807 hospitalised cases or deaths and 68 confirmed deaths. Investigators identified vitamin E acetate, an additive found mainly in illicit THC (cannabis) vaping products, as a primary cause. It was found in lung fluid from 48 of 51 patients tested and in none of the comparison group. The CDC noted that other chemicals could not be ruled out in some cases. The UK review warned that mixing up EVALI with regulated nicotine vaping has misled people about the relative risks.
Popcorn lung. This is a rare, serious lung disease linked to a flavouring chemical called diacetyl, first seen in workers at popcorn factories. Cancer Research UK reports no confirmed cases of popcorn lung caused by vaping, and diacetyl has been banned from e-liquids in the UK since 2016.
The lesson from both: what is in the device matters. The worst harms seen so far came from illicit products, so stick to regulated ones and never add other substances.
Vaping as a way to quit smoking
For smokers, the most practical part of the vaping vs smoking question is whether vaping helps you stop. The evidence here is the strongest it has ever been.
The Cochrane living review, last updated in November 2025, now includes more than 100 studies and over 30,000 participants. Its key findings:
- Against nicotine replacement therapy (patches, gum and similar products), nicotine e-cigarettes helped more people stay off cigarettes for at least six months. The risk ratio was 1.55, based on high-certainty evidence. In practical terms, about 9 in 100 people quit with nicotine e-cigarettes, compared with about 6 in 100 using nicotine replacement.
- Against nicotine-free e-cigarettes, the nicotine versions probably work better (moderate-certainty evidence).
- Side effects most often reported were throat or mouth irritation, headache, cough and feeling sick, and these eased over time.
One of the largest single trials, published in the New England Journal of Medicine in 2019, randomised 886 smokers in UK stop smoking services. After one year, 18.0% of those given e-cigarettes had quit, compared with 9.9% of those given nicotine replacement. One trade-off: 80% of those who quit with e-cigarettes were still vaping at one year, while only 9% of quitters in the nicotine replacement group were still using it.
Once you stop, the recovery starts quickly. Our quit smoking timeline shows what changes in the first hours, months and years.
Guidance differs between countries. In the UK, the NHS and stop smoking services support vaping as a quit aid. In the US, no e-cigarette is approved by the FDA as a quit aid, and the US Preventive Services Task Force has said the evidence is insufficient to recommend them. The CDC states that e-cigarettes may benefit adults who smoke and are not pregnant, but only if used as a complete substitute for smoked tobacco.
How to switch from smoking to vaping
If you choose to switch, these steps give you the best chance:
- Switch completely. The benefit comes from stopping smoking, not from adding a vape.
- Use enough nicotine. Too little can leave cravings unmet and pull you back to cigarettes. A stop smoking adviser can help you choose a strength.
- Buy from regulated retailers. Avoid illicit products and never add other substances.
- Get support. Combining a quit aid with behavioural support raises your chances, whatever method you use.
- Plan to stop vaping later. Once you are confident you will not smoke again, aim to come off nicotine entirely.
Dual use: vaping and smoking together
Many people who start vaping keep smoking some cigarettes too. This is called dual use, and it is where much of the potential benefit is lost.
Cutting down is not enough to protect your heart. A 2018 BMJ analysis found that, for men, smoking just one cigarette a day carried nearly half the extra heart disease risk of smoking 20 a day, which is why the heart health benefit comes from stopping, not reducing. UK guidance, including from NICE, is that everyone who smokes should be supported to stop smoking completely, including dual users. The CDC puts it more bluntly: dual use is not an effective way to protect your health.
Many people do use both for a while as they switch. If that is you, treat it as a short phase on the way to stopping cigarettes, not as a place to stay.
If you do not smoke, do not start
Every advantage vaping has comes from replacing cigarettes. For someone who does not smoke, there is nothing to replace, so vaping only adds risk.
- Nicotine addiction. The OHID review found substantial evidence that vaping can cause nicotine dependence, even if the risk and severity appear lower than for smoking.
- A route into smoking. NASEM found substantial evidence that young people who use e-cigarettes are at higher risk of trying cigarettes.
- Higher exposure than not vaping. Compared with people who use no nicotine, vapers have similar or higher levels of harmful substances.
The CDC states that e-cigarettes are not safe for young people, young adults, pregnant adults or adults who do not already use tobacco. If you are a non-smoker looking for help with stress, focus or weight, nicotine is not the answer.
Frequently asked questions
Is vaping safer than smoking?
For an adult who smokes and switches completely, yes. In the vaping vs smoking comparison, reviews from NASEM and the UK government found that vaping exposes users to far fewer and lower levels of toxic chemicals than smoking. It is not risk-free, and its long-term effects are not yet known.
Is vaping bad for your lungs?
Vaping aerosol is not harmless, and some users report cough and throat irritation. Compared with smoking, exposure to chemicals linked to lung disease is much lower. The most serious lung injuries reported in the US were mainly linked to illicit THC products containing vitamin E acetate.
Does vaping affect your heart?
Nicotine raises heart rate and blood pressure in the short term, and some short-term studies show effects on artery stiffness. Biomarkers linked to heart disease are much lower in vapers than in smokers. Long-term heart outcomes have not yet been studied.
Can vaping help you quit smoking?
Yes. The Cochrane review found high-certainty evidence that nicotine e-cigarettes help more people stop smoking than nicotine patches or gum. The goal should be to stop smoking completely and, over time, stop vaping too.
Is it worse to vape and smoke at the same time?
Using both is unlikely to be worse than smoking alone, but it gives little health benefit while you keep smoking. The gains come from stopping cigarettes completely.
The bottom line
On vaping vs smoking, the evidence is consistent: for adults who smoke, switching completely to vaping greatly reduces exposure to the chemicals that cause disease, and it helps more people quit than nicotine replacement. But vaping is not harmless, its long-term effects are still unknown, and using both products gives little benefit. If you smoke, use vaping as a route out of cigarettes and then off nicotine. If you do not smoke, do not start.
This article is for general information and is not medical advice. Talk to your doctor, pharmacist or a stop smoking service for support with quitting, especially if you are pregnant or have a heart or lung condition.
Sources
- Office for Health Improvement and Disparities: Nicotine vaping in England, 2022 evidence update main findings
- Office for Health Improvement and Disparities: Nicotine vaping in England, 2022 evidence update summary
- National Academies of Sciences, Engineering, and Medicine: Public Health Consequences of E-Cigarettes (2018)
- Lindson N et al. Electronic cigarettes for smoking cessation. Cochrane Database of Systematic Reviews, 2025
- University of Oxford: Electronic cigarettes for smoking cessation, Cochrane living systematic review
- Hajek P et al. A Randomized Trial of E-Cigarettes versus Nicotine-Replacement Therapy. New England Journal of Medicine, 2019
- CDC: CDC, States Update Number of Hospitalized EVALI Cases and EVALI Deaths (2020)
- CDC: About Electronic Cigarettes
- Cancer Research UK: Does vaping cause popcorn lung?
- Hackshaw A et al. Low cigarette consumption and risk of coronary heart disease and stroke. BMJ, 2018
- The Conversation: How the “95% less harmful” figure took off