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Scientific assessment of tobacco heating technology

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Composition of aerosol emitted by heating tobacco

By eliminating combustion, the levels of harmful are on average 95% lower compared to those in cigarette smoke.*

Important information: It does not necessarily equal a 95% reduction in risk. IQOS is not risk-free. Heated tobacco products contain nicotine, which is addictive.

*Average reductions in levels of a range of harmful chemicals (excluding nicotine) compared to the smoke of a reference cigarette (3R4F).
microscope with smoke

How is aerosol being tested?

We have been studying the chemical composition of a variety of aerosols for over a decade. Based on the guidelines and regulations of health authorities, such as the World Health Organisation*, U.S. Food and Drug Administration ** we have consolidated a list of 58 chemicals that are relevant to the analysis of cigarette smoke and smoke-free aerosols. The list contains constituents that may pose health risks to humans – which is why our products are specifically designed to reduce them at the lowest possible levels.

Through careful monitoring, we are able to determine whether we can effectively reach our aim of eliminating or substantially reducing these constituents. Besides targeting known constituents, we also perform analyses to identify constituents that may emerge via the evolution of our products.

*WHO Study Group on Tobacco Product Regulation Report on the Scientific Basis of Tobacco Product Regulation. WHO Technical Report Series, no. 951 ISBN: 978 92 4 120951 9 2008 on 01 January 2008.
**Federal register. Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke; Established List. A Notice by the Food and Drug Administration on 04/03/2012.
person arm sampling

Comparing cigarette smoke and heated tobacco aerosol

We measured a number of harmful chemicals in the aerosol of heated tobacco and compared it to the levels found in the smoke of a standard reference cigarette (3R4F). On average, a 95% reduction in the levels of harmful and potentially harmful chemicals in heated tobacco aerosol was observed.*

In order to ensure that the use of new technologies does not introduce any new risk to adult smokers when compared to the use of cigarettes, we perform analyses to determine whether any new or unexpected chemical compounds are present in the aerosol. In addition to the quantitative analysis of 58 harmful and potentially harmful constituents, we also adopt a strategy for the comprehensive, non-targeted screening of Reduced Risk Product aerosols

Important information: It does not necessarily equal a 95% reduction in risk. IQOS is not risk-free. Heated tobacco products contain nicotine, which is addictive.

* Average reductions in levels of a range of harmful chemicals (excluding nicotine) compared to the smoke of a reference cigarette (3R4F).
*Schaller, J. P., et al. (2016). Evaluation of the Tobacco Heating System 2.2. Part 2: Chemical composition, genotoxicity, cytotoxicity, and physical properties of the aerosol. Regul Toxicol Pharmacol 81 Suppl2: S27-S47.
volumetric balloon

Aerosol chemistry

IQOS tobacco vapour is less harmful than cigarette smoke. To demonstrate this, we conducted a comprehensive assessment programme that included 10 clinical studies on aerosol chemistry (as well as data from 18 non-clinical studies), and involved thousands of participants in the US, Japan, UK and Poland. Evidence demonstrates that switching completely to IQOS, while not risk-free, presents less risk of harm compared with continuing to smoke cigarettes.

The comprehensive chemical characterization of heated tobacco aerosol using untargeted analytical screening methods revealed that a total of 532 chemical constituents (including water, glycerin, and nicotine, which were measured using different methods) were present at concentrations ≥ 100 ng/heated tobacco unit.*

All compounds that were detected in aerosol ≥ 100 ng/heated tobacco unit were also found to be present in smoke from the standard reference cigarette 3R4F. Only a minority of compounds in heated tobacco aerosol were present at concentrations exceeding those measured in cigarette smoke.

*Bentley, M. C., et al. (2020). Comprehensive chemical characterization of the aerosol generated by a heated tobacco product by untargeted screening. Anal Bioanal Chem 412:2675-2685. 20 U.S.
**Food and Drug Administration. Premarket Tobacco Product Marketing Order TPL (Technical Project Lead Review); PM0000424-79. 29 Apr 2019; Section 6 – Summary of Toxicological Findings: p42.
person doing science

What is important to know about tar?

Tar is the weight of solid and liquid residue in cigarette smoke, after nicotine and water have been removed. So, is tar measurement useful? If we only take the weight into account, no it’s not.

According to World Health Organization, “Tar need not be measured, as it is not a sound basis for regulation, and the levels can be misleading.”* When people consider the risk of harm of a product in relation to tar it’s more important to look at the content of the residue rather than its weight.

When we look at the content of cigarette smoke, there are thousands of chemicals released and of those the U.S. Food and Drug Administration has listed 93 known toxicants. It is the presence of and exposure to these chemicals that plays a role in the development of smoking-related diseases, not the tar measurement.

Heated tobacco does not produce tar because tobacco heating system heats tobacco, instead of burning it. Heated tobacco generates an aerosol residue that is fundamentally different from “Tar” and consists of significantly lower levels of harmful chemicals.**

Important information: Although IQOS does not produce tar, IQOS is not risk free. Heated tobacco products contain nicotine, which is addictive.

*World Health Organization (2015). WHO study group on tobacco product regulation: Report on the scientific basis of tobacco product regulation: Fifth report of a WHO study group. WHO Technical Report Series, no. 989.
** Average reductions in levels of a range of harmful chemicals (excluding nicotine) compared to cigarette smoke.

Aerosol effect on teeth staining

Aerosol, emitted by using heated tobacco products, leaves significantly less stains on teeth than cigarettes.

Teeth that had cavities filled with dental resins were exposed to cigarette smoke or aerosol for four days a week, followed by brushing and incubation. After three weeks of such exposure, color match, marginal discoloration, marginal integrity, and surface texture of the restoration were assessed according to a modified U.S. Public Health Service criterion.

Marked discoloration of enamel and dentin was observed following 3 weeks of cigarette smoke exposure, and color mismatch occurred between the composite resin restorations and dental hard tissues. Discoloration was minimal in the enamel, dentin, and composite resin restorations in the aerosol group, and no color mismatch was observed after 3 weeks of heated tobacco aerosol exposure.*

Important information: If teeth are already stained, switching to IQOS will not reverse the color of those stains.

Please, find our verification programs here:

*Zanetti, F., et al. (2019). Effects of cigarette smoke and tobacco heating aerosol on color stability of dental enamel, dentin, and composite resin restorations. Quintessence Int 50(2): 156-166.

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