The product science of electrically heated tobacco products: a narrative review of the scientific literature

Heated tobacco products represent a novel category of tobacco products in which a tobacco consumable is heated to a temperature that releases nicotine from the tobacco leaf but not to a temperature sufficient to cause combustion. Heated tobacco products may therefore have the potential to be a less harmful alternative for adult smokers that would otherwise continue to smoke conventional cigarettes. Given the rapid development of this product category, the aim of this review was to examine the available peer-reviewed scientific evidence related to heated tobacco products and highlight any research gaps. In recent years, manufacturers of heated tobacco products have published a number of studies on their respective heated tobacco products. Whilst there is limited research that is independent of commercial interests, the available scientific evidence indicates that heated tobacco products produce a much simpler aerosol than conventional cigarette smoke, with fewer and substantially lower levels of harmful toxicants. Toxicology assessments indicate these reductions in aerosol toxicants translate to reduced biological effects. Biomarker and clinical data from studies in which product use is controlled within a clinical setting, indicate changes in biomarker levels and clinical end-points similar to observations in cessation studies, indicating the potential for reduced harm. The scientific evidence also indicates that exposure of non-users to emissions from heated tobacco products in indoor environments is significantly reduced compared to exposure resulting from smoking conventional cigarettes. Overall, the available scientific evidence indicates that heated tobacco products hold promise as a less harmful alternative to conventional cigarettes, but more independent data is required to validate industry findings. As a growing product category, epidemiological studies and independent population modelling studies are outstanding, and empirical data on how dual tobacco product category use by consumers affects their risk profile is lacking.