Cigarette smoking remains the leading preventable cause of disease and premature death worldwide [1, 2]. Traditional tobacco control efforts have focused primarily on preventing initiation and promoting cessation. While these approaches remain central pillars, many individuals continue to struggle with long-term abstinence, often cycling through relapse and remission [3, 4]. This persistent burden underscores the need for complementary strategies, such as tobacco harm reduction (THR), which is formally acknowledged in the World Health Organization’s Framework Convention on Tobacco Control [5].
THR is grounded in the principle that while nicotine use sustains dependence, it is the inhalation of toxicants produced by the combustion of tobacco that is primarily responsible for smoking-related diseases such as cancer, cardiovascular disease, and respiratory illness [6, 7]. Nicotine itself, although addictive, is not the chief culprit in the pathogenesis of these conditions.
By transitioning from combustible cigarettes to non-combustible nicotine delivery systems—including electronic cigarettes (ECs), heated tobacco products (HTPs), and oral products such as snus and nicotine pouches—smokers can substantially reduce their exposure to harmful constituents.
Among these alternatives, combustion-free products like ECs, HTPs, and oral nicotine pouches have been consistently shown to emit far fewer toxic substances, with chemical exposure levels ranging from markedly lower to negligible compared to traditional cigarettes.
In a study of 181 participants, exclusive EC users showed a 97% reduction in NNAL, a carcinogenic biomarker, compared to cigarette smokers. Levels of 1,3-butadiene and acrylonitrile—major tobacco-related carcinogens—were also drastically lower (11.0% and 2.9%, respectively) [8]. These reductions in carcinogens were confirmed in the large, nationally representative PATH study involving 17,830 adults [9]. Similar evidence supports that HTPs reduced toxicant exposure compared to smoking. In a 12-month RCT with 506 smokers, HTP users showed marked reductions in toxicants (e.g., NNAL, 4-ABP, S-PMA), reaching levels comparable to abstainers [10]. A second large trial (n = 984) found similar results after 6 months of switching to IQOS [11]. Also, both ECs and HTPs eliminate elevated exhaled CO levels, a key cardiovascular risk marker, with normalization observed rapidly after switching [12, 13].
Extensive research on snus, a smokeless tobacco product widely used in Sweden, shows substantially reduced exposure to harmful toxicants compared to combustible cigarettes. Snus users exhibit significantly lower levels of biomarkers such as NNAL, S-PMA (a benzene biomarker), and 1-HOP (a PAH biomarker), often approaching the levels observed in never-smokers [14]. Notably, Swedish men, who have among the highest rates of snus use in Europe, also display some of the lowest tobacco-related disease rates, including lung cancer and cardiovascular disease—supporting the product’s harm reduction potential [15]. Similarly, nicotine pouches, which contain pharmaceutical-grade nicotine but no tobacco leaf, offer even cleaner toxicological profiles. Independent chemical analyses confirm that modern pouches contain few to no detectable tobacco-specific nitrosamines (TSNAs) or other combustion-related toxicants [16]. While long-term population-level data are still limited, early studies suggest that nicotine pouches deliver nicotine with minimal exposure to harmful or potentially harmful constituents (HPHCs)—comparable to or lower than those of NRT products (17).
Over the past 6 years since its inception, the topical collection titled “Health Impact of Electronic Cigarettes and Heated Tobacco Systems” has published nearly 40 peer-reviewed articles. The collection has accumulated an aggregated Altmetric score of close to 3,000, reflecting strong engagement across both academic and public platforms. Collectively, these articles have garnered over 200,000 views and downloads and have been cited nearly 500 times, underscoring the collection’s influence and relevance in advancing and disseminating the scientific discourse on novel nicotine delivery products within the public health and clinical research communities.
Building on this success and in response to the growing interest in and use of oral nicotine and tobacco products, the Springer editorial team and Internal and Emergency Medicine are doubling down by relaunching and expanding the collection under a new title: “Health Effects of E-Cigarettes, Heated Tobacco and Oral Nicotine Products.”
This expanded focus reflects the evolving landscape of nicotine delivery technologies, the surge in consumer interest, and the mounting need for rigorous research on their health effects.
Emerging data suggest that oral nicotine delivery systems—including nicotine pouches and Scandinavian snus—are additional alternatives that are smoke-free, discreet, and less harmful than cigarettes. Like ECs and HTPs, these products raise important questions around individual risk, population health impact, regulatory frameworks, and public perceptions. While they differ in pharmacokinetics, sensory profiles, and cultural acceptance, all three product categories share a common feature: they deliver nicotine without combustion, and thus offer meaningful harm reduction.
We encourage researchers to submit studies addressing a wide spectrum of topics, including toxicological profiles and comparative risk assessments, cardiovascular and respiratory health outcomes, biomarker studies, the effectiveness of these products in smoking cessation or substitution, patterns of dual and poly-use, as well as public health modeling and regulatory policy implications.
We also welcome contributions that examine the behavioral, psychological, and social dimensions of these products, particularly in high-risk or underserved populations. Submit your manuscript here: https://link.springer.com/collections/fdbcibeagj.
As the landscape of non-combustible nicotine alternatives continues to evolve, it is essential that public health policy be guided by rigorous, transparent, and evidence-based research. These investigations are particularly relevant to the internal medicine community, as clinicians are increasingly encountering patients who use alternative nicotine products and must navigate their cardiopulmonary, metabolic, and behavioral health implications across diverse clinical settings. By expanding the scope of this topical collection, Internal and Emergency Medicine reaffirms its commitment to fostering critical discourse and advancing both clinical understanding and public health knowledge in this rapidly developing field.
We encourage investigators, clinicians, and public health scholars to contribute to this important conversation and help build a balanced, science-driven understanding of how electronic cigarettes, heated tobacco products, and oral nicotine/tobacco products impact human health.