18B.1 Types of heated tobacco products

Last updated: May 2024           

Suggested citation: Winnall, WR. 18B.1 Types of heated tobacco products. In Greenhalgh EM, Scollo, MM and Winstanley, MH [editors]. Tobacco in Australia: Facts and issues. Melbourne: Cancer Council Victoria; 2024. Available from https://www.tobaccoinaustralia.org.au/chapter-18-e-cigarettes/indepth-18b-non-combustible-cigarettes/18b-1-types-of-heated-tobacco-products

 

Heated tobacco products are different from e-cigarettes in that they contain tobacco, which is heated to produce an aerosol. A wide range of heated tobacco products have come to market and are presently sold in over 50 countries, 1 but they are effectively prohibited in Australia (see Indepth 18B.9). Differences between these devices in design and operation may influence the amount of nicotine and toxicants delivered to the user. 2 In light of rapid changes in the market, the World Health Organization recommends: continuous monitoring to identify new products and changed features of products and emissions; premarket review of new products before entering the market; and stringent regulation in line with other tobacco products. 2

18B.1.1 How heated tobacco products work

Early heated tobacco products contained no electronic components; they heated tobacco in a stick that resembled a cigarette. Most contemporary devices have electronic holders that heat tobacco sticks. These tobacco sticks also resemble cigarettes and usually come with filters. Some devices combine a heated nicotine liquid with tobacco.

Heated tobacco products use a heat source to release nicotine and/or other chemicals, such as flavourants, from tobacco. These devices heat the tobacco to a lower temperature (up to 350°C) than occurs during combustion in conventional cigarettes (800 to 900°C). Combustion is not necessary to release nicotine and flavourants from tobacco, so a lower temperature heat is sufficient to efficiently transfer these chemicals into the aerosol emissions. Many other chemicals, including toxic ones, also make up this aerosol. See InDepth 18B.5 for more details about the contents of the aerosol emissions from heated tobacco products.

18B.1.2 Heating functions

Heated tobacco products vary widely but include two main components: a heating device and a tobacco source (often called sticks). Devices currently on the market also contain a power supply from a rechargeable battery. 2 , 3 The World Health Organization’s Study Group on Tobacco Product Regulation (TobReg) suggests classifying heated tobacco products by their heating mechanisms 2 and describes four types of heating devices.

See Table 18B.2.1 in InDepth 18B.2 for a summary of the heated tobacco devices developed and brought to market.

Embedded heating source

The earliest devices used a heating source embedded into the tobacco sticks, in which a pressed carbon tip is set alight, transferring heat into the tobacco. A match or lighter is used to light the carbon tip, resulting in a heating temperature of approximately 350°C. 3 These tobacco sticks looked similar to conventional cigarettes, had no electrical components and were disposed of once smoked. Embedded heating sources were used in early devices such as Premier (released in the late-1980s) and Eclipse (early-1990s) and Philip Morris’s “Platform 2” (2017). 2

External heating source

External heat sources are currently the most popular. For these devices, a tobacco stick is inserted into an electronic holder, with a protruding mouth-piece that usually contains a filter. The device heats the tobacco stick, which is smoked by the user for approximately five minutes. After use, the tobacco stick is discarded.

Heets-blade
Figure 18B.1.1 A schematic of the external heating system (in yellow) for early IQOS devices, with tobacco stick inserted. Image from this licence.

The external heating source is located in the electronic components of the device, rather than part of the tobacco stick. These external heating sources usually contact the tobacco in specially designed sticks that resemble cigarettes (see example in Figure 18B.1.1). In IQOS devices (Philip Morris International and Altria, see Figure 18B.1.2), a heating blade is pushed into the tobacco once a tobacco stick is inserted into the device. The IQOS device is designed not to exceed 350°C. 2 The glo product (British American Tobacco, Figure 18B.1.2) is described as having a heated tube into which tobacco sticks are inserted. 4 This tube heats the tobacco to 240°C, according to the company. 3 , 4 Accord (produced by Philip Morris US in 1998) and Heatbar (released by Philip Morris International in 2006) were devices that also used an external heating source. 2 Recent innovations in IQOS devices (commercialised in 2021 and 2022) replaced the heated blades with either an induction system that activates a heating element inside the tobacco stick, or by heating the tube in which the tobacco stick is inserted. 5 Glo products (British American Tobacco) from 2019 onwards have also included induction heating. The manufacturer states that these products reach a temperature of between 240 and 280°C. 6

IQOS 01 Glo POLAR EDITION プルームテックデバイス
Figure 18B.1.2 Examples of common heated tobacco devices and tobacco sticks. On the left is IQOS (image from this licence), in the middle is glo (image from this licence) and on the right is Ploom (image from this licence).

Hybrid devices

Hybrid devices are similar to e-cigarettes in that a liquid is heated to produce an aerosol, which travels through tobacco to incorporate flavours and possibly nicotine. Examples of these are iFuse (British American Tobacco) and Ploom (Japan Tobacco International, Figure 18B.1.2). These devices look similar to e-cigarettes and require a rechargeable battery. 2 At least in the iFuse device, the heating of the tobacco appears to occur at much lower temperature compared to IQOS or glo. 2 As the tobacco is not heated to a high temperature, the amount of toxic chemicals transferred from the tobacco to the emissions is predicted, by the manufacturers, to be relatively low and similar to that of e-cigarettes. 2 The 2019 glo product called glo sens also appears to be a hybrid device, similar to Ploom. 7

Loose-leaf vaporisers

Loose-leaf vaporisers heat a sealed chamber (like a small oven) containing ground tobacco. The user must fill the chamber with ground tobacco leaf, from which nicotine will be aerosolised with once heated. Interestingly, although PAX (Pax labs) was initially created for tobacco use, its marketing appears to be mostly targeting cannabis users. 8

18B.1.3 Tobacco and other ingredients

In general, the tobacco sticks used in heated tobacco products contain less tobacco than conventional cigarettes (which ranged from 412 mg to 774 mg per cigarette in Australia in 2020 (see Section 12.1.4)). IQOS’s tobacco sticks are 45 mm long and 7 mm diameter. They contain approximately 320 mg of tobacco material. The tobacco in IQOS is reconstituted, containing between 5–30% added polyols, glycol esters and fatty acids, which are likely used to promote aerosol formation. 2 According to the manufacturers, IQOS products from the THS2.2 range contain added glycerol, guar gum and cellulose fibres. 9 Menthol is also added to some IQOS products. The glo product heats an 82 mm by 5 mm diameter tobacco stick containing approximately 260 mg of reconstituted sheet tobacco with 14.5% glycerol (a common component of e-liquids for e-cigarettes) added for aerosol formation. 2 The tobacco used in glo is described as blended Virginia tobacco. 4 The iFuse hybrid product has a cartridge containing 1.86 mg/ml nicotine in a liquid solution. This is heated and passed over the tobacco to gain tobacco flavour. Undisclosed additives create flavours in glo and Ploom, such as ‘citrus’ flavour.

Whilst the tobacco sticks have been branded with their own names, there have been instances of more traditional tobacco brand names such as Marlboro. 10

18B.1.4 Batteries

Most heated tobacco products contain rechargeable lithium-ion batteries. Early devices that use a pressed carbon tip do not need batteries, as the heat comes from the carbon tip once lit. 2 Batteries in one contemporary device are claimed to hold sufficient charge for 14,600 ‘sessions’ by the manufacturer. 5 Some devices have a two-step charging process, whereby the tobacco stick holder is charged within a larger charging unit. The charging unit itself must then be recharged after 2 to 20 uses, depending on the device. Other devices are an all-in-one unit that the tobacco stick is inserted into and is directly charged via a USB cable. 

18B.1.5 Modes of use and user experiences

Contemporary devices heat the tobacco relatively quickly, and are ready for use in less than a minute after activation. The most popular devices usually have two modes of use, which may differ in the time and heating conditions before the first puff. This can affect the flavour of the first puff. The ability of the user to modify the experience of heated tobacco, however, is minimal compared to e-cigarette modifications (see Section 18.1.1.1).

External heating and hybrid devices require cleaning between uses with brushes and cloths to remove the ash and residue. Users report a characteristic tobacco smell of the smoke exhaled from the device.

An investigation by Reuters’ reporters proposed that IQOS devices could extract information about a user’s smoking routine from the device. They predicted that a microcontroller chip in the device could support the storing of usage information that could be transmitted back to the manufacturer, and that this data could include details such as the number of puffs taken by a user and how many times a person smoked the device per day. 11 Ploom devices also have Bluetooth-enabled connections between devices and smartphone apps.

Relevant news and research

For recent news items and research on this topic, click here. (Last updated May 2024)

References

1. Bialous SA and Glantz SA. Heated tobacco products: another tobacco industry global strategy to slow progress in tobacco control. Tobacco Control, 2018; 27(Suppl 1):s111-s7. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30209207

2. WHO Study Group on Tobacco Product Regulation. Report on the scientific basis of tobacco product regulation: eighth report of a WHO study group. WHO Technical Report Series, No. 1029.Geneva, Switzerland: WHO, 2021. Available from: https://www.who.int/publications/i/item/9789240022720.

3. World Health Organization. Heated tobacco products: a brief. Denmark: WHO, 2020. Available from: https://www.who.int/europe/publications/i/item/WHO-EURO-2020-4571-44334-62636.

4. Eaton D, Jakaj B, Forster M, Nicol J, Mavropoulou E, et al. Assessment of tobacco heating product THP1.0. Part 2: Product design, operation and thermophysical characterisation. Regulatory Toxicology and Pharmacology, 2018; 93:4-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29080851

5. Philip Morris International. Over 30 years of innovation.  Available from: https://booklet.pmiscience.com/ths-evolution-html/index.html.

6. British American Tobacco. Our flagship tobacco heating product.  Available from: https://www.bat.com/group/sites/UK__CRHJSY.nsf/vwPagesWebLive/DOCS4JK8#.

7. Seung-hyun S. BAT launches liquid-type e-cigarette Glo Sens in Korea. The Investor,  2019. Available from: http://www.theinvestor.co.kr/view.php?ud=20190813000662

8. Business Wire. PAX unveils all new lineup for cannabis flower and concentrate vaporization.  2022. Available from: https://www.businesswire.com/news/home/20221101005215/en/PAX-Unveils-All-New-Lineup-for-Cannabis-Flower-and-Concentrate-Vaporization.

9. Smith MR, Clark B, Ludicke F, Schaller JP, Vanscheeuwijck P, et al. Evaluation of the Tobacco Heating System 2.2. Part 1: Description of the system and the scientific assessment program. Regulatory Toxicology and Pharmacology, 2016; 81 Suppl 2:S17-S26. Available from: https://www.ncbi.nlm.nih.gov/pubmed/27450400

10. Tobacco Tactics. Heated tobacco products: Philip Morris International.  2023. Available from: https://tobaccotactics.org/article/heated-tobacco-products-philip-morris-international/.

11. Lasseter T, Wilson D, Wilson T, and Bansal P. Part 5: Philip Morris device knows a lot about your smoking habit.  2018. Available from: https://www.reuters.com/investigates/special-report/tobacco-iqos-device.