Heated tobacco products may reduce exposure to some combustion-related toxicants compared to combustible cigarettesHeated tobacco products may lower exposure to some toxins

Smoking remains one of the leading preventable causes of morbidity and mortality worldwide, significantly contributing to the healthcare burden. Despite decades of public awareness, many people are unable to quit combustible cigarette (CC) smoking due to nicotine dependence and/or limited access to effective cessation support. Various alternative tobacco products such as e-cigarettes, heated tobacco products (HTPs) and nicotine pouches have been promoted as lesser harm alternatives; among which HTPs have received increasing attention lately. However, these products differ substantially in their composition, patterns of use, and potential health effects. This narrative review evaluates evidence on HTPs relative to CCs across four distinct levels: (i) product emissions, (ii) biomarkers of human exposure, (iii) indicators and evidence relevant to individual disease risk, and (iv) potential population-health impact. These levels are considered separately because reduced emissions or exposure cannot, by itself, establish reduced clinical disease, mortality, or net population benefit. Compared to combustible cigarettes, HTPs may lessen exposure to some combustion-related toxicant, but they are not risk-free; their population-health impact depends on who takes up these products and under what social and cultural circumstances, the frequency, intensity and duration of use, exclusive versus dual or poly use, users’ prior exposure and health status, and the wider institutional, infrastructural and regulatory environment. To guide effective policy formulation for harm reduction based on evidence further longitudinal epidemiological and policy-evaluation studies across diverse settings are needed to assess long-term health outcomes and determine how tobacco-control and harm-reduction strategies—including public communication and education, taxation, product regulation and cessation support—shape awareness, risk perceptions, product uptake and substitution, patterns and intensity of use, cessation and relapse.