2 | Is vaping safe? Scientific evidence and health vs Tobacco

Is vaping safe? Health, science and comparison with tobacco

The right question is not whether vaping is “harmless”, but how it compares with combustible tobacco. The scientific evidence is clear: for an adult smoker, completely switching from smoking to vaping substantially reduces exposure to combustion toxicants.

This content is intended for adult smokers. Vaping is not recommended for minors, non-smokers, pregnant women or people with medical concerns without first consulting a healthcare professional.

1. Smoke versus vapour: the key scientific difference

The main harm from smoking does not come only from nicotine. It comes above all from combustion: burning tobacco and paper produces smoke with tar, carbon monoxide and thousands of chemical compounds, many of them toxic or carcinogenic.

Vaping works differently: it heats an e-liquid to form an aerosol. There is no tobacco combustion. This radically changes the exposure profile. It does not make vaping risk-free, but it explains why harm reduction bodies place it far below combustible tobacco in relative risk for adult smokers. ^{[1] [3]}

2. What harm reduction really means

Harm reduction does not mean saying that vaping is healthy. It means comparing real risks between two behaviours: continuing to smoke combustible tobacco or replacing it with a non-combustion alternative.

In that framework, the available evidence supports a strong conclusion: vaping is substantially less harmful than smoking combustible tobacco for an adult smoker who switches completely. ^{[1] [3]}

3. The 95% figure: useful, but it must be explained correctly

The phrase “around 95% less harmful than smoking” comes from British reviews associated with Public Health England. It should not be read as an exact mathematical figure that applies to every product, user or pattern of use.

It does communicate the essential idea correctly: the relative risk gap between smoking combustible tobacco and vaping as a complete substitute is very large. Combustion is the major source of harm, and vaping removes it. ^[2]

4. Evidence on quitting smoking: Cochrane and clinical trials

The Cochrane living systematic review, one of the strongest references in evidence-based medicine, concludes that nicotine e-cigarettes increase quit rates compared with traditional nicotine replacement therapy such as patches or gum, with high-certainty evidence. ^[4]

This does not mean they work magically or for everyone. It means something more specific and more important: when used properly, with a realistic nicotine strategy and complete replacement of smoking, they are an effective tool for adult smokers who want to quit smoking.

5. Comparative toxicology: what studies measure

Emission, biomarker and exhaled breath studies allow us to compare which substances appear in tobacco smoke, vaping aerosol and the air exhaled by the user. Here the difference is again clear: combustible tobacco generates a much more aggressive chemical load.

A study from IDAEA-CSIC, published in Journal of Chromatography A by Esther Marco and Joan O. Grimalt, analysed volatile organic compounds in cigarette smoke, electronic cigarettes and exhaled breath. The study observed marked differences between tobacco and vaping: tobacco smoke and the exhaled breath of smokers showed a much higher load of volatile organic compounds, including benzene, toluene, naphthalene and other pollutants of general concern. ^[7]

This study does not prove that vaping is harmless, but it reinforces a central fact of harm reduction: by removing tobacco combustion, the exposure profile changes dramatically. For an adult smoker, fully replacing combustible cigarettes with vaping reduces exposure to many of the compounds characteristic of tobacco smoke.

6. Dual use: the big nuance

Dual use means smoking and vaping at the same time. From a harm reduction point of view, it is clearly worse than complete switching, because the smoker remains exposed to combustion smoke.

Reducing cigarettes may be a first step, but the important jump happens when the smoker stops smoking combustible tobacco. As long as cigarettes remain, there is still exposure to tar, carbon monoxide and combustion toxicants.

7. Minors, non-smokers and pregnancy: no grey area

Vaping should not be promoted to minors or people who do not smoke. In these groups there is no tobacco substitution benefit, while risks may exist, especially when nicotine is involved.

During pregnancy, nicotine can affect fetal development. As a health precaution, a pregnant woman or someone planning pregnancy should consult a healthcare professional and avoid nicotine exposure unless it is part of a supervised medical plan. ^[5]

Clear message: harm reduction is not a universal invitation to vape. It is a strategy for adult smokers who want to leave combustible tobacco behind.

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Main scientific references

1. Office for Health Improvement and Disparities. Nicotine vaping in England: 2022 evidence update. Official report.
2. Public Health England. E-cigarettes around 95% less harmful than tobacco estimates: landmark review. GOV.UK.
3. Royal College of Physicians. E-cigarettes and harm reduction: An evidence review. RCP report.
4. Cochrane Library. Electronic cigarettes for smoking cessation. Cochrane review.
5. World Health Organization. Tobacco: E-cigarettes. WHO page.
6. Dusautoir R. et al. Comparison of the chemical composition of aerosols from heated tobacco products, electronic cigarettes and tobacco cigarettes. PubMed.
7. Marco, E., & Grimalt, J. O. (2015). A rapid method for the chromatographic analysis of volatile organic compounds in exhaled breath of tobacco cigarette and electronic cigarette smokers. Journal of Chromatography A, 1410, 51–59. PMID: 26243705. PubMed.

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