A European study highlights 134 toxins present in electronic cigarettes and heated tobacco

A study published in the journal Nicotine & Tobacco Research and conducted by several European research institutes concludes that electronic cigarettes and heated tobacco, two distinct products – one vaping and the other tobacco – but often presented together and wrongly placed in the same category, contain 134 substances that pose a direct health risk.[1]. This research is part of Joint Action on Tobacco Control 2 (JACT2), which aims to provide scientific support for the implementation of the European Tobacco Products Directive (TPD) and the recommendations of the World Health Organization (WHO). The researchers warn that the presence of these substances, banned in tobacco and nicotine products, could justify the withdrawal from the market of certain products, even though manufacturers present them as less harmful "alternatives" to traditional tobacco.

Hundreds of substances identified in e-cigarettes and heated tobacco

For this study, French, Norwegian, Spanish, Greek, and Dutch researchers identified 1,740 substances in products and their emissions. The ingredients were identified using data provided by Belgium, France, the Netherlands, and Sweden to the EU-CEG (European Union Common Entry Gate) database, in which manufacturers are required to declare the composition of their products.

Thus, 1,301 substances were found in electronic cigarettes and 88 in heated tobacco products.

In parallel, a systematic review of the literature identified 284 substances in the emissions of electronic cigarettes and 380 in those of heated tobacco products.

Some of these substances are dangerous, and the manufacturers know this.

The 1,740 substances identified were classified into three categories according to available toxicological knowledge: category 1 includes substances presenting the highest risk, category 2 those considered potentially harmful, and category 3 those for which current data are insufficient.

Of all the substances identified, 134 fall into the priority category. These include volatile organic compounds, tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, and metals.

These substances include carcinogenic, mutagenic, reprotoxic, chronically toxic, respiratory irritant or endocrine disruptor compounds, some of which have multiple effects.

Researchers note that in e-cigarettes, some of these substances were present both as ingredients and in emissions, indicating that despite their well-documented dangers, manufacturers knowingly incorporate these substances.

Researchers are calling for a stronger regulatory framework and greater transparency around these new products.

The authors believe these results highlight shortcomings in the enforcement of current regulations and underscore the need for stricter enforcement of existing bans. This comes as the latest OECD report on cardiovascular health in the EU shows that vaping among people aged 15 and over in the EU increased by 45%, reaching 4% in 2024, raising concerns about the emergence of new nicotine consumption patterns.[2].

They recommend that authorities use the proposed classification to enforce the provisions of the European Union Tobacco Products Directive (2014/40/EU), which entered into force in 2016, particularly regarding the prohibition on adding certain substances as additives. Indeed, Articles 7 and 20 of the Tobacco Products Directive (TPD) stipulate that harmful substances classified in category 1 of this study may not be added to tobacco and nicotine products as additives, and Article 20.3(e) of the TPD concerning ingredients in e-liquids stipulates that substances whose safety for human health has not been proven in categories 2 and 3 may also not be added to the products.

The researchers also suggest strengthening the directive to require more information on ingredients and emissions from manufacturers, to define technical requirements to limit exposure to harmful substances such as metals (fixed power settings, power and/or temperature range for the resistance…), and to extend and harmonize the regulatory framework to nicotine-free products that may still be harmful, such as nicotine-free e-cigarettes, herbal products or tobacco substitutes.

They also call for better public information on the health risks associated with the use of these products.

Other independent works published in recent years, In particular, the in-depth analysis conducted by the Tobacco Control Research Group at the University of Bath and a meta-analysis published in 2025 in Tobacco Control already raised specific concerns about heated tobacco. These researchers emphasized that, currently, research on heated tobacco relies primarily on trials largely funded by the industry. The studies focus on limited periods of use, primarily short-term, and are highly controlled, failing to reflect the true harmfulness of these products. Consequently, the immediate and long-term health effects of heated tobacco remain insufficiently documented, an uncertainty exploited by manufacturers in their "harm reduction" marketing strategy to expand the market for their new products.

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[1]Maya El Bouz, Clara Neto, Thibault Mansuy, Rune Becher, Håkon Valen, Espen Mariussen, Daniela Alejandra Blanco-Escauriaza, Adrián González-Marrón, Efthimios Zervas, Anne Havermans, Reinskje Talhout, Yvonne CM Staal, Health Hazards of E-Cigarettes and Heated Tobacco Products: a Comprehensive Analysis of Hazardous Substances and Regulatory Gaps,Nicotine & Tobacco Research, published December 6, 2025, accessed December 22, 2025

[2]OECD, The State of Cardiovascular Health in the European Union, OECD Publishing, published in 2025, accessed on December 22, 2025