RESEARCH

      Our findings on the Tobacco Heating System

      At Philip Morris International (PMI), we conduct a rigorous scientific assessment program on our heated tobacco products (HTPs), built around our research expertise in fields including chemistry, biology, medicine, behavioral science, and data sciences. PMI’s Tobacco Heating System (THS), commercialized as different product versions under the IQOS brand, is our most thoroughly assessed HTP. Learn more about the key results we have gathered on THS. 

      Understanding our research outcomes 

      PMI conducts rigorous scientific studies to substantiate the harm reduction potential of switching to THS compared with continued cigarette smoking. THS electrically heats a uniquely processed tobacco plug to release a nicotine-containing aerosol without burning.  

      We have accumulated nonclinical and clinical data to support the potential of THS to reduce the risk of smoking-related harm compared with cigarettes. Through our scientific assessment program, we have demonstrated that no combustion occurs during THS use, and the aerosol generated contains an average of 90-95% lower levels of harmful and potentially harmful constituents (HPHCs) than found in cigarette smoke. 

      At each step of our assessment program, we apply rigorous standards that correspond to national regulations and internationally recognized research guidelines, principles, and practices. The program is guided by the 2012 draft guidance for modified risk tobacco product (MRTP) applications issued by the U.S. Food and Drug Administration’s Center for Tobacco Products. 

      Our research covers a wide range of topics including: 

      • Aerosol chemistry and indoor air quality 
      • Toxicology 
      • Clinical studies 
      • Initiation and usage patterns 
      • Long-term impact 

      On this page, you can discover our research findings on the THS. These studies contribute to a deeper understanding of the risk-reduction potential of our HTPs and the role they can play in tobacco harm reduction efforts. 

      Aerosol science and indoor air quality research 

      The aerosol studies we conduct aim to confirm that burning does not take place during the use of the THS. They also show that the resulting aerosol contains lower levels of HPHCs compared with cigarette smoke and is fundamentally different from it. Our research also seeks to precisely measure the impact of THS use on indoor air quality.

      Explore our studies on aerosol science and indoor air quality related to THS. 

      • No burning, no smoke

        Info highlight

      • Lower levels of harmful chemicals

        Info highlight

      • Liquid droplets, no solid particles

        Info highlight

      • No adverse effect on indoor air quality

        Info highlight

      • Similar results in different environments and puffing regimes

        Info highlight

      Toxicology research 

      PMI’s toxicological investigations explore the question of whether THS aerosol is toxic to cells and other laboratory models compared with cigarette smoke. They also allow scientists to understand the biological processes (called adverse outcome pathways) that lead from exposure to the onset of smoking-related diseases. Results of PMI’s studies involving cell cultures and nonclinical methods indicate that THS presents reduced toxicity compared with cigarettes, although this product is not risk free and release nicotine, which is addictive.  

      Learn more about how our studies provide an indication of the reduced-risk potential of THS. 

      • Less toxic than smoke

        Info highlight

      • No increase in lung tumors, emphysema, or atherosclerosis

        Info highlight

      • Less teeth discoloration

        Info highlight

      Clinical studies

      Clinical studies aim to evaluate the effects of our smoke-free products on human health outcomes. Our clinical studies involve volunteers and are conducted according to strict, internationally recognized guidelines, national regulations, and ethical standards. These studies provide important human data on the use and acceptance of THS products and their potential to reduce the risk of smoking-related diseases as compared with continued smoking.  

      Learn more about our comprehensive clinical findings related to THS. 

      • Potentially reduced disease risk

        Info highlight

      • Lower level of exposure

        Info highlight

      • Nicotine uptake comparable to cigarettes

        Info highlight

      Research on initiation and usage patterns 

      At PMI, we conduct initiation and usage studies to gauge how our THS products are used and by whom, and to understand and assess the potential impact of these products on public health. The scientific research data to date show low initiation rates among nonusers of tobacco or nicotine-containing products and the propensity of adult smokers to switch to THS. 

      Explore our research on initiation and usage of THS. 

      • Low initiation among never TNP users

        Info highlight

      • low intention to use among nonsmokers

        Info highlight

      • Adult smokers likely to switch to THS

        Info highlight

      Long-term impact assessment 

      Continued monitoring of the impact of THS use over the long term is vitally important to ensuring that these products continue to reduce the risk of harm as compared with continuing smoking. PMI’s long-term assessment includes safety surveillance programs that allow us to track and rapidly respond to any adverse effects associated with the use of our smoke-free products. We have developed the population health impact model (PHIM), an epidemiological model to estimate the potential population-level health impact of smoke-free products in different countries. 

      Find out more about our long-term studies related to THS and harm reduction. 

      • Safety surveillance studies

        Info highlight

      • Population Health Impact Model (PHIM)

        Info highlight

      • Japan: declining cigarette sales

        Info highlight
      Related articles
      Isquare: Inside The Cube: Philip Morris International Research and Development Center
      PMI’s progress toward a smoke-free future
      Discover PMI's commitment to innovation and harm reduction as we work towards a smoke-free future and replacing cigarettes with less harmful alternatives for smokers worldwide.
      Gloved hand holding test tube
      Milestones in Tobacco Heating System research
      PMI answers questions about some of the key scientific research relating to THS and what this can tell us about the harm-reduction potential of smoke-free products.
      PMI Science Booklet
      PMI Science Booklet
      Discover PMI's latest research on smoke-free alternatives in our PMI Science Booklet. Explore heat-not-burn and e-vapor technologies, and our vision for a smoke-free future.
      A large crowd of people on street square.
      Harm reduction and smoke-free products
      Learn about harm reduction strategies including smoke-free products, as well as PMI's efforts to further public health and tobacco research.

      PMIScience.com is operated by Philip Morris International for the purpose of publishing and disseminating scientific information about Philip Morris International’s efforts in support of its smoke-free product portfolio. This site is a global site for use by scientists, the public health and regulatory communities, and other stakeholders with an interest in tobacco policy. The purpose of this site is not advertising or marketing, nor is it directed at any specific market. It is not intended for use by consumers. New tobacco products sold in the United States are subject to FDA regulation; therefore the content of this site is not intended to make, and nor should it be construed as making, any product related claims in the United States without proper FDA authorization. ​
      ​
      Reduced Risk Products ("RRPs”) is the term we use to refer to products that present, are likely to present, or have the potential to present less risk of harm to smokers who switch to these products versus continuing smoking. PMI has a range of RRPs in various stages of development, scientific assessment and commercialization. All of our RRPs are smoke-free products that deliver nicotine with far lower quantities of harmful and potentially harmful constituents than found in cigarette smoke.