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Fact Sheet

Electronic Cigarettes

Dec 2021


This fact sheet provides an introduction to the function and uses of electronic cigarettes, as well as exploring the perceptions and impacts of vaping and how this can be used to support the cessation of smoking.


The COVID-19 pandemic is the subject of much ongoing research and it is too early to assess its full impact on vaping and smoking at the time of writing. It has affected the implementation of routine surveys and has also likely affected both vaping and smoking behaviours in England.1

Key points

  • Electronic cigarettes, e-cigarettes and vapes are all terms used to describe a battery-powered device which allows its user to inhale nicotine through a vapour rather than smoke.2
  • Evidence to date shows that e-cigarettes are substantially less harmful than cigarettes and can be effective for helping people quit smoking.1 3
  • E-cigarettes have caused much debate among the public health community, with some taking a cautionary approach whereas others see e-cigarettes as an innovation which is supporting hardened smokers to quit.3 4
  • The public continue to misperceive the relative harms of e-cigarettes, considering them to be more or equally as harmful as smoking.5
  • Regular e-cigarette users are mostly adults who are already smokers, there is no evidence that e-cigarettes are "renormalizing smoking or increasing smoking uptake.3
  • There is strong evidence that e-cigarettes contain nicotine are effective for smoking cessation and reduction.1
  • Great Britain no longer has to comply with the EU’s Tobacco Products Directive and there is opportunity to consider, in the future, further regulatory changes that help people quit smoking and address the harms from tobacco.6

Types of e-cigarette

E-cigarettes, also known as vaporisers or electronic nicotine delivery systems (ENDS), are battery-powered devices that deliver nicotine by heating a solution containing nicotine, flavourings and other additives. They consist of a mouthpiece, battery and cartridge or tank containing the nicotine solution. When a user sucks on the e-cigarette, a sensor activates a heating element (atomiser) which heats the liquid in the cartridge or tank so that it evaporates. The vapour delivers the nicotine to the user.

There are three main types of e-cigarettes:

  • ‘Cig-a-like’ products: The first generation of e-cigarettes were designed to resemble tobacco cigarettes and often have a light at the end that glows when the user draws on the device to resemble a lit cigarette. These products include non-rechargeable disposable models and reusable models with rechargeable atomisers and replaceable cartridges.
  • ‘Tank’ models, also known as vape pens: An e-cigarette with a rechargeable atomiser and a tank which has to be filled with a nicotine e-liquid. These models allow the user to choose from a range of nicotine strengths and flavourings and are the most popular.
  • ‘Mods’, or advanced personal vaporisers: A more complex tank model which can be manually customised, for example by adjusting the voltage on the device.

E-cigarettes, cigarettes and nicotine replacement therapy

The primary function of e-cigarettes is to deliver nicotine, as with tobacco cigarettes and nicotine replacement products you can buy in a pharmacy.7

Smokers are not addicted to tobacco: they are addicted to nicotine.8 Most smokers continue to smoke despite wanting to quit because nicotine is a remarkably addictive drug. However, smokers don’t die from exposure to nicotine.9 It’s the cocktail of other chemicals that is produced when tobacco is burnt that does the harm. E-cigarettes and nicotine replacement therapy products, such as gum, lozenges, patches and sprays, offer alternative ways of getting nicotine into your body without having to inhale tobacco smoke.1

The following are key differences between tobacco cigarettes and e-cigarettes, in the context of their regulation in the UK:

  • Tobacco has been smoked in Britain for over 400 years and the survival of cigarettes and other tobacco products in today’s regulated market is a historical anomaly. It would be impossible to bring a product as toxic as a cigarette to market today. The regulation of tobacco products is not therefore focused on their content – which is unavoidably toxic – but on their advertising, display, packaging and use.
  • Nicotine replacement therapy (NRT) products are licensed medicines, designed to help people quit smoking. NRT products deliver nicotine without all the toxic chemicals that are produced when tobacco is burnt. Nicotine itself is relatively safe, though highly addictive. NRT products have to be rigorously tested for safety in order to get a licence as a medicine from the Medicines and Healthcare products Regulatory Agency (MHRA). Smokers who use NRT to quit smoking may in time also stop using NRT; others continue to use NRT to meet their need for nicotine.
  • E-cigarettes have similar characteristics to both cigarettes and NRT products. Like tobacco cigarettes, they deliver nicotine via inhalation: they are designed to mimic the experience of smoking. Like NRT products, they deliver nicotine without the tar and toxic chemicals that smokers inhale. However, unlike NRT products, they are not medicines, or at least none of the products currently on the market in Britain have been licensed as medicines. Instead they are regulated as consumer products under the UK Tobacco and Related Products Regulations 2016. E-cigarettes are recognised to be far safer than tobacco products (see below) but they have not been tested for safety as rigorously as NRT products.

Although e-cigarettes are more like NRT in their effects and toxicity, they look more like cigarettes in their everyday use.9 The action of vaping an e-cigarette is, however, fundamentally different to that of smoking a cigarette. When a person smokes a conventional cigarette, smoke from the burning tobacco is inhaled into the lungs and then exhaled.8 Smoke is also emitted from the burning tip of the cigarette, releasing toxins into the air: this is the main source of the toxic second-hand smoke breathed by bystanders. In contrast, there is no combustion involved in vaping an e-cigarette. Vapour is released when the user sucks on the e-cigarette, and the only vapour emitted into the air is that which the user exhales.8

E-cigarettes are used by millions of people in the UK

E-cigarettes are overwhelmingly used by ex-smokers and current smokers. It is estimated that there are over 3.6 million adults in Great Britain using e-cigarettes – 7.1% of the adult population.10 Of these e-cigarette users in 2021, 64.6% of current vapers were ex-smokers, while 30.5% also smoked (dual users).11 The proportion of adult smokers who have tried e-cigarettes has continued to grow, while those who have never tried continues to decline.11

People use e-cigarettes for a variety of reasons.9 The vast majority for health reasons, to help them quit, prevent relapse or cut down the amount they smoke. Vapers also report using e-cigarettes to save money compared to smoking, to protect others from second-hand smoke and because it gives them pleasure.12

E-cigarette users also have diverse attitudes to their vaping. Some perceive their use of e-cigarettes as a way of managing their nicotine addiction and keeping off cigarettes; others think of vaping simply as a pleasure which they intend to enjoy in the long term. A third group, who are likely still to smoke, feel ambivalent about their e-cigarette use and do not think of themselves as ‘vapers’.12

For more information, see the ASH Factsheet: Use of e-cigarettes among adults in Great Britain: 2021

Vaping is far safer than smoking

Vaping an e-cigarette is much less harmful than smoking a tobacco cigarette because tobacco smoke is not inhaled. Most of the toxins in tobacco smoke are not found in the vapour of e-cigarettes and those that are present are at much lower levels – mostly below 1%.3 15

The active ingredient of e-cigarettes is nicotine. Nicotine, when inhaled in smoke, is a highly addictive drug, which absorbs the time, money and attention of its users.9 But long-term use of nicotine consumed through NRT has not been found to increase the risk of serious health problems. A review of the efficacy and safety of NRT in pregnancy found that NRT increased smoking cessation rates, measured in late pregnancy, by approximately 40%.13 The authors found no evidence that NRT used for smoking cessation in pregnancy has either positive or negative impacts on birth outcomes.14

There are some health risks associated with the other ingredients of e-cigarettes, but they are low compared to tobacco products. In particular:

  • Propylene glycol and glycerine, components of e-liquids, can produce toxic aldehydes if they are overheated. Fortunately overheating also creates a bad taste that puts off the user. At normal vaping temperatures, the quantity of aldehydes produced is only a small fraction of the levels inhaled by smokers.
  • Flavourings could pose a risk to health but there is currently no evidence that any flavourings used by e-cigarette manufacturers present a significant risk to their users.
  • Metals have been identified in e-cigarette vapour but at concentrations so low that their risk to health is minimal.

E-cigarettes are not completely safe. But compared to tobacco products, they are clearly the safer choice. For example, the lifetime cancer risk of vaping has been assessed to be under 0.5% of the risk of smoking.15

Although not all of the risks of e-cigarettes have been fully investigated, and the long-term effects of vaping are as yet unknown, the 2018 assessment by Public Health England is that vaping is at least 95% less harmful than smoking: “Vaping poses only a small fraction of the risks of smoking and switching completely from smoking to vaping conveys substantial benefits over continued smoking.” This is consistent with the findings of the Royal College of Physicians in 2016 that “the hazard to health arising from long-term vapour inhalation from the e-cigarettes available today is unlikely to exceed 5% of the harm from smoking tobacco”.16

There is also a risk of fire from the electrical elements of electronic cigarettes, and a risk of poisoning from ingestion of e-liquids, but these risks are comparable to those of other electrical goods and poisonous household substances. Current regulations help to reduce these risks by specifying childproof containers. Clear user instructions are also important: e-liquid bottles should be stored away from medicines, the correct charger should always be used, and e-cigarettes should not be carried in pockets with coins, keys or other metallic objects.

Unfortunately, while evidence of the relatively low health risks posed by e-cigarettes has grown over time, so has public misunderstanding of these risks. In 2021, a quarter (32%) of adults in Great Britain thought that e-cigarettes were more harmful or as harmful as smoking tobacco, up from 7% in 2013.17 In 2021, 50% perceived e-cigarettes to be less harmful (30%) or a lot less harmful (12%) than smoking while 24% ‘did not know’.11

The risk to others from e-cigarette vapour is negligible

E-cigarette users can sometimes generate large clouds of vapour which to bystanders may look as troublesome as a cloud of cigarette smoke. Yet to date no risks have been identified of ‘passive vaping’.

As the risk to vapers of inhaling e-cigarette vapour is low, the risk to those who breathe their exhaled vapour is even lower: concentrations of vaping-related chemicals are simply too low to have any impact. Furthermore, most secondhand tobacco smoke comes from the burning tip of the cigarette, not the smoker, but there is no such ‘sidestream’ vapour produced by e-cigarette users.18

For further information see the ASH briefing: Will you permit or prohibit electronic cigarette use on your premises?

E-cigarettes help smokers quit

Vaping is positively associated with quitting smoking successfully. Findings from a recent report commissioned by Public Health England, (PHE) demonstrated that e-cigarettes are the most popular aid used in quit attempts.1 In 2020, 27.2% of people used a vaping product in a quit attempt in the previous 12 months, compared with 15.5% who used NRT over the counter or on prescription (2.7%) and 4.4% who used varenicline.1 In 2020, more than half (64%) of the e-cigarette users in Great Britain were ex-smokers. Among all ex-smokers, nearly one in ten (9.5%) regularly used e-cigarettes. It is abundantly clear that e-cigarettes have played, and continue to play, an important role in helping people quit smoking and stay smokefree.1 5

The use of e-cigarettes by smokers who want to quit smoking increases their chance of success. A major UK clinical trial published in 2019 found that, when combined with expert face-to-face support, people who used e-cigarettes to quit smoking were twice as likely to succeed as people who used other nicotine replacement products, such as patches or gum.19 20 21 The National Institute for Health and Care Excellence (NICE) has, for the first time, included vaping products, also known as electronic cigarettes, as a recommended stop smoking aid in its newly released tobacco guidelines.22 The guidelines mean that alongside providing clear and up-to-date information about vaping products, stop smoking services should also make these products accessible to adults who want to use them to quit. The most recent guidance for health professionals from the National Institute for Health and Care Excellence (NICE) is available online.22

In addition, the National Centre for Smoking Cessation and Training (NCSCT) has produced professional guidance: Electronic cigarettes: a briefing for stop smoking services. This briefing recommends that stop smoking services should be open to e-cigarette use in people keen to try them to help them quit. This is especially so in those who have tried and failed to quit using licensed stop smoking medicines.

E-cigarettes are not a gateway to smoking

To date, there is no evidence that significant numbers of non-smokers are experimenting with e-cigarettes and subsequently becoming smokers. E-cigarettes have proved to be an important gateway out of smoking, not into it. The behaviour of young people has been a particular concern. However, analysis of data from the 2021 ASH YouGov Smokefree youth GB survey suggests that while some young people experiment with e-cigarettes, particularly those who have tried smoking, regular use remains low.23 Furthermore, the prevalence of regular e-cigarette use by young people who had never smoked was negligible (between 0.1% and 0.5%). Overall, there is no evidence that e-cigarettes have driven up smoking prevalence in this age group.24 In fact, smoking prevalence among young people has declined since e-cigarettes came onto the market. However, continued surveillance is needed.

For more information, see Use of e-cigarettes among young people in Great Britain

The tobacco industry is now a major producer of e-cigarettes

Globally, the market for tobacco products is still far bigger than the market for e-cigarettes. Nonetheless, as the e-cigarette market has grown, the tobacco industry has taken an ever-increasing stake in it:

  • Imperial Brands owns Blu
  • PMI (Phillip Morris International) owns Nicocigs
  • BAT (British American Tobacco) owns Vype
  • JTI (Japan Tobacco International) owns E-Lites
  • Reynolds American owns Vuse
  • Altria owns MarkTen


  • [1]

    McNeill, A., Brose, L.S., Calder, R., Simonavicius, E. and Robson, D. (2021). Vaping in England: An evidence update including vaping for smoking cessation, February 2021: a report commissioned by Public Health England. London: Public Health England

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    About Electronic Cigarettes (E-Cigarettes) | Smoking & Tobacco Use | CDC [Internet]. [cited 2021 Dec 15].

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    McNeill A, Brose LS, Calder R, Bauld L & Robson D. Evidence review of e-cigarettes and heated tobacco products 2018. A report commissioned by Public Health England. London: Public Health England

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    Royal College of Physicians. Nicotine without smoke: Tobacco harm reduction. London: RCP, 2016.

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    Online survey by YouGov for ASH. Total sample size was 12,247 adults. Fieldwork was undertaken between 18th February - 18th March 2021. The survey was carried out online. The figures have been weighted and are representative of all GB adults (aged 18+).

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    NHS Using e-cigarettes to stop smoking. [Internet]. 2018 [cited 2021 Dec 15].

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    Pfeffer D, Wigginton B, Gartner C, Morphett K. Smokers’ Understandings of Addiction to Nicotine and Tobacco: A Systematic Review and Interpretive Synthesis of Quantitative and Qualitative Research. Nicotine & Tobacco Research, 2018

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    Marques P, Piqueras L, Sanz M-J. An updated overview of e-cigarette impact on human health. Respiratory Research, 2021.

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    Methodology: Calculations are by ASH and Dr Leonie Brose at King’s College London. In each of the years we applied the proportions of e-cigarette use by smoking status in the YouGov survey to the most recent available ONS mid-year GB population estimates at the time the YouGov data was gathered. In 2021 ONS mid-year GB population estimates for 2019 have been used.

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    Online survey by YouGov for ASH. Total sample size was 12,247 adults. Fieldwork was undertaken between18th February - 18th March 2021. The survey was carried out online. The figures have been weighted and are representative of all GB adults (aged 18+).

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    Farrimond H. A typology of vaping: Identifying differing beliefs, motivations for use, identity and political interest amongst e-cigarette users. International Journal of Drug Policy Volume 48, Pages 81–90 2017.

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    Coleman T, Chamberlain C, Davey MA, Cooper SE, Leonardi‐Bee J. Pharmacological interventions for promoting smoking cessation during pregnancy. Cochrane Database Syst Rev. 2015; (12):CD010078.

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    Coleman T, Chamberlain C, Davey MA, Cooper SE, Leonardi‐Bee J. Pharmacological interventions for promoting smoking cessation during pregnancy. Cochrane Database Syst Rev. 2015; (12):CD010078.

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    Stephens WE. Comparing the cancer potencies of emissions from vapourised nicotine products including e-cigarettes with those of tobacco smoke. Tobacco Control. 2017

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    Royal College of Physicians. Nicotine without smoke: Tobacco harm reduction. London: RCP, 2016.

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    Online survey by YouGov for ASH. Total sample size was 12,171 GB adults. Fieldwork was undertaken between 1st and 19th February 2013. The figures have been weighted and are representative of all GB adults (aged 18+).

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    Klepeis NE, Bellettiere J, Hughes SC, Nguyen B, Berardi V, Liles S, et al. Fine particles in homes of predominantly low-income families with children and smokers: Key physical and behavioral determinants to inform indoor-air-quality interventions. PloS One. 2017;12(5):e0177718

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    Beard E, West R, Michie S, and Brown J Association between electronic cigarette use and changes in quit attempts, success of quit attempts, use of smoking cessation pharmacotherapy, and use of stop smoking services in England: time series analysis of population trends. BMJ 2016;354:i4645

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    Hajek P, Phillips-Waller A, Przulj D, Pesola F, Myers Smith K, Bisal N, et al. A Randomized Trial of E-Cigarettes versus Nicotine-Replacement Therapy. N Engl J Med Massachusetts Medical Society; 2019

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    Brown J, Beard E, Kotz D, Michie S & West R. Real-world effectiveness of e-cigarettes when used to aid smoking cessation: a cross-sectional population study. Published online 20 May 2014.

  • [22]

    National Institute for Health and Care Excellence (NICE) Tobacco: preventing uptake, promoting quitting and treating dependence (NG209)| Guidance 2021 | NICE; [cited 2021 Dec 21].

  • [23]

    2021 ASH Smokefree GB Youth Survey. Total sample size was 2,513 respondents. The online survey was undertaken between 25th March– 16th April 2021. The figures have been weighted and are representative of all GB children aged 11 to 18

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    Bauld L et al Young People’s Use of E-Cigarettes across the United Kingdom: Findings from Five Surveys 2015-2017, International Journal of Environmental Research and Public Health 2017, 14, 29 August 2017