Over the summer, we’re producing a short series of articles that summarise the core policy debates around safer nicotine products. We’ve taken a lot of inspiration from the most recent set of policy briefings produced by Clive Bates: the full briefings are available here.
Smoking is probably the most harmful consumer behaviour that’s still legal, posing significant risks for multiple cancers, cardiovascular diseases, and respiratory conditions. The harm comes from thousands of toxic or carcinogenic chemical agents produced when you burn tobacco leaves. You could set fire to almost anything and be presented with a similar set of nasties. But smoking involves intentionally inhaling them when you smoke, making them all the more deadly.
7.69 million deaths are attributable to smoking every year, so finding safer alternatives to smoking has huge potential to improve public health. Alternatives like vaping.
But how do we know that vaping is safer? The media often reports that we “don’t have enough evidence” to say for sure that vaping is far safer. But the truth is that we have over a decade’s worth of compelling evidence. This article will summarise and explain three kinds of evidence as a starting point: chemical evidence, biomarker evidence and health indicator evidence.
Chemical evidence
Chemical evidence is a good starting point. Scientists can analyse what comes out of cigarettes and vapes, and tell us what’s in them and how harmful it is.
Cigarettes deliver nicotine through the combustion of tobacco, which generates over 7,000 chemical agents, including at least 158 known toxic or carcinogenic substances. Vaping devices heat a liquid containing nicotine, flavorings, and other chemicals to create an aerosol that the user inhales. This switch from combustion to aerosolization drastically reduces the number and concentration of harmful chemicals the user is exposed to.
Several high-quality, independent reviews have consistently concluded that vapes contain only a small fraction of the chemical risks associated with smoking at much lower levels. The National Academies of Sciences, Engineering, and Medicine (2018) noted that a variety of laboratory tests and short-term human studies all suggest that e-cigarettes are significantly less harmful than combustible tobacco cigarettes. Public Health England has repeatedly stated that vaping is "at least 95% less harmful than smoking" a figure intended to communicate the substantial risk reduction in a clear and actionable manner.
Put simply: we can independently verify what’s in the vapour an e-cigarette produces, compare it to the smoke a cigarette produces, and determine that the risk of the latter is far lower than the risk of the former.
Biomarker evidence
But the evidence is far stronger than that. In fact, some of the most compelling evidence for the reduced harm of vaping comes from biomarker studies, which measure the levels of toxicants in users' blood, saliva, or urine after they smoke or vape. This goes further than telling us the harmful substances contained in what the user inhales; it tells us how much of each substance the body takes in and processes.
These kinds of studies consistently show that switching from smoking to ENDS leads to a dramatic reduction in actual human exposure to hazardous chemicals. Many biomarkers of exposure fall to background levels or below the limit of detection, and most others are significantly reduced. This reduction in toxicant levels translates to substantial health benefits for those who make the switch from smoking to vaping.
Put simply: we can independently verify how many harmful chemicals enter the body after smoking and vaping When compared, far fewer harmful chemicals are found in the bodies of vapers, and most of those are at very low levels.
Health indicator evidence
Finally, we can look at health indicators, meaning measurable improvements to the health of individuals who switch from smoking to vaping. These improvements include better lung function, reduced respiratory disease symptoms, lower blood pressure, and reduced risk factors for cardiovascular disease.
For example, one study found ‘significant and consistent’ improvements in the lung function of COPD (Chronic Obstructive Pulmonary Disease) patients who switched from smoking to vaping; another concluded that those who quit smoking using e-cigarettes do not experience high blood pressure; and a third found a significant reduction in self-reported respiratory infections among those who switched. One study even found that the cancer potency of ENDS is just 0.4% of that of cigarette smoke, further underscoring the significant reduction in health risks associated with vaping.
Put simply: when we monitor the physical health of former smokers who switch completely to vaping, we find consistent and measurable improvements in their health.
So why the confusion?
While critics of vaping often raise concerns about potential health effects, these concerns are often based on misunderstandings or flawed research methods. For example, many studies that find associations between vaping and health effects fail to adequately account for the participants' long histories of smoking. When studies follow individuals through their transition from smoking to vaping, they consistently show substantial reductions in harmful biomarkers and improvements in health outcomes.
The evidence overwhelmingly supports the conclusion that vaping is significantly safer than smoking. By eliminating the combustion process and the associated release of toxic chemicals, vaping offers a far less harmful alternative for nicotine delivery. While it is not without risks, these risks are minor compared to the well-documented dangers of smoking.
