E-cigarettes: The Basics

This page was last edited on at

This page gives a basic summary of what e-cigarettes are, how they work and what they contain. It does not attempt to describe or assess their safety.

What Are E-cigarettes?

E-cigarettes, also known as electronic cigarettes or electronic nicotine delivery systems (ENDS), work by heating a nicotine containing liquid, producing emissions usually described as a ‘vapour’. They consist of a battery, a cartridge (disposable, replaceable or refillable) with liquids (called ‘e-liquids’) and a heating mechanism. This heats the cartridge ingredients to create a ‘vapour’ that is inhaled by the consumer. They do not contain tobacco and there is no combustion or smoke, but some emit ‘clouds’ resembling vapour. Odour is produced by flavours which are added to the liquid. E-cigarettes are used like conventional cigarettes: when the user draws on an e-cigarette, a visible cloud of aerosol is produced, mimicking the smoke of a conventional cigarette. With some ‘cig-a-likes’ (see below) a simulator LED light mimics the glow of a conventional cigarette.

What Different Types Are There?

Two diagrams of e-cigarettes, tank style and cartridge style

Figure 1: Common types of e-cigarettes.1

Many e-cigarettes are manufactured to look like conventional cigarettes, cigars, or pipes.while others resemble everyday items such as pens and USB memory sticks. Some models are single use, often called ‘disposable’. Some are designed to be refilled with cartridges (or ‘pods’) and some are also rechargeable, for instance via USB.

Vapourisers and ‘tank systems’ tend to be bigger, including ‘mods’ (from ‘modification’) which allow the user to assemble or customise their device, for example by changing size or battery power.

Detailed descriptions of different types of e-cigarette can be found on Wikipedia: Electronic cigarette

What Are ‘Vapes’?

Tobacco industry product terminology changes with developments in products, shifts in business strategy and new marketing tactics. As for other newer nicotine and tobacco products, the terms used to refer to e-cigarettes have changed over time.

Tobacco companies now generally refer to all their e-cigarettes as ‘vapes’, short for ‘vapouriser’ (‘vaporizer’ in the US), which has the effect of distancing them from conventional cigarettes.2 On their company websites in 2022, British American Tobacco (BAT) and Imperial Brands referred to their e-cigarettes as ‘vapour products’;34 Philip Morris International (PMI) used the term ‘e-vapor’;5 and only Japan Tobacco International (JTI) referred to their current products as ‘e-cigarettes’.6

What Is In E-liquids?

The liquids used in most e-cigarettes are usually sold in a bottle or in pre-filled disposable cartridges and may include nicotine as well as variable combinations and quantities of water, glycerol, propylene glycol, flavourings and other ingredients. A huge number of flavours are available, from tobacco and menthol flavours to those resembling sweets, like bubble gum, or cherry or strawberry. The latter are prohibited for use in regular cigarettes because of concerns that such flavours appeal to children.

In late 2019, US President Donald Trump announced an intention to ban e-cigarette flavours in the US, with the possible exemption of some flavours such as tobacco and menthol.789 After lobbying from the e-cigarette industry, it appeared that the ban would be watered down to exclude menthol and tobacco flavours, and would continue to allow fruit and sweet flavoured e-liquids to be sold for re-fillable ‘tank’ devices.10111213

How Much Nicotine?

E-liquids are sold in different nicotine concentrations. In some countries the level of nicotine in e-cigarettes is restricted. In the European Union the maximum concentration allowed is 20mg/ml (20%). In the US, as of 2020, there is no maximum level set by law, and some e-cigarettes (including JUUL Labs’ JUUL) contain much higher levels, up to three times that amount.14 In other countries, including Australia, it is illegal to sell products containing nicotine without a licence, and therefore e-liquids containing nicotine are not openly available without a prescription.

It is also possible to buy flavoured liquids for e-cigarettes without nicotine (labelled 0% nicotine). Some tobacco companies sell these liquids, although the majority of their products contain nicotine.

Nicotine can be extracted from tobacco leaf in different ways for use in e-liquids. The most common ‘freebase’ method enables nicotine to pass through membranes in the body more easily, but can be harsh on the throat when inhaling higher concentrations. A more recent innovation is ‘nicotine salts’, which are created when ‘freebase’ nicotine is dissolved in acid. This method can make a higher dose of nicotine more palatable and so allow higher doses of more concentrated nicotine to be consumed.15 Juul e-cigarettes use nicotine salts. All four transnational tobacco companies (BAT, PMI, JTI, Imperial Brands) also sell nicotine salt products.

TobaccoTactics Resources

Relevant Links

Print Friendly, PDF & Email


  1. Images adapted from: M. A. Orellana-Barrios, D. Payne, Z. Mulkey, K. Nugent, Electronic Cigarettes—A Narrative Review for Clinicians, The American Journal of Medicine, Volume 128, Issue 7, 2015, Pages 674-681, doi:/10.1016/j.amjmed.2015.01.033.
  2. A. Hancock, Big Tobacco seeks to recast with tech-focused workforceFinancial Times, 19 June 2019, accessed October 2019 (behind paywall)
  3. British American Tobacco, Vapour Products, BAT website, undated, accessed October 2022
  4. Imperial Brands, Brands of Choice, website, undated, accessed October 2022
  5. Philip Morris International, Smoke Free Products, PMI website, undated, accessed October 2022
  6. Japan Tobacco International, Our reduced-risk products – our vaping products, JTI website, undated, accessed October 2022
  7. Trump says FDA will ban flavoured e-cigarettes to combat teen vaping, The Guardian, 11 September 2019, accessed November 2019
  8. J. Wingrove, G. Porter Jr, M. Cortez, Trump Considers Retreat From Ban of Mint, Menthol Vaping Flavors, Bloomberg, 25 October 2019, accessed November 2019
  9. J. Hellmann, FDA working as quickly as possible on e-cigarette flavour ban, The Hill, 25 October 2019, accessed November 2019
  10. A. Karni, M. Haberman, S. Kaplan, Trump Retreats from Flavor Ban for E-Cigarettes, The New York Times, 17 November 2019, accessed January 2020 (paywall)
  11. A. Goodnough, M. Haberman, S. Kaplan, With Partial Flavor Ban, Trump Splits the Difference on Vaping, The New York Times, 2 January 2020, accessed January 2020 (paywall)
  12. J. Howard, Trump administration to clear market of most e-cigarette cartridge flavors, but not menthol, CNN, 2 January 2020, accessed January 2020
  13. US announces countrywide ban on flavoured e-cigs, BBC, 2 January 2020, accessed January 2020
  14. M. Nedelman, New bill aims to cap nicotine levels in e-cigarettes, CNN, 7 October 2019, accessed October 2019
  15. Centre for Media and Democracy, Freebase Nicotine, Sourcewatch, 27 September 2017, accessed July 2019