Clinical Assessment

Our clinical studies provide human data on the use and acceptance of our smoke-free products as well as their potential to reduce exposure to harmful chemicals and the potential to reduce the risk of smoking-related diseases as compared to continued smoking.

Clinical studies are a cornerstone of the assessment program. They help determine the extent to which adult smokers would find the product an acceptable alternative to cigarettes; assess whether a reduction in the formation of harmful and potentially harmful constituents (HPHCs) measured in the laboratory leads to a reduction in HPHC exposure under real use conditions when an adult smoker switches to the product; and investigate whether switching from cigarettes to a candidate reduced-risk product has a beneficial effect on a smoker’s health profile.

1. Pharmacokinetics / Pharmacodynamics

When switching IQOS, the nicotine uptake and urgeto-smoke scores were similar to those measured in subjects who continued smoking.


We have shown that the level of nicotine, and the timing of its peak concentration in the blood, were comparable for smokers and for subjects who switched to IQOS. Furthermore, the urge-to-smoke scores were similar for smokers and switchers. This suggests that switchers do not seek to use IQOS more frequently than smokers seek to use cigarettes, and that switchers can find IQOS acceptable and satisfying.

The chart shows our findings concerning the relative in vitro toxicity of IQOS aerosol compared with the smoke from the 3R4F reference cigarette using three in vitro assays (Neutral Red Uptake, Ames and Mouse Lymphoma) commonly used to assess cytotoxicity and genotoxicity. (Reference)

2. Exposure to HPHCs

We found that smokers switching to IQOS were exposed to lower levels of harmful chemicals compared to those who continued smoking.


In our 5-day and 90-day clinical reduced exposure studies, we measured biomarkers in the blood and urine representing exposure to selected harmful chemicals. We found that levels of 15 biomarkers of exposure in participants switching to IQOS were comparable to the levels of those who quit smoking for the duration of the study. In both cases, the levels remained well below those observed in subjects who continued smoking during the study.

The same type of study in the U.S. (NCT01989156) showed comparable results.

Lüdicke, F., et al. (2018). Effects of switching to the Tobacco Heating System 2.2 menthol, smoking abstinence, or continued cigarette smoking on biomarkers of exposure: a randomized, controlled, open-label, multicenter study in sequential confinement and ambulatory settings (Part 1). Nicotine Tob Res 20(2): 161-172. (Reference)
Our clinical studies are registered on
The ID of the presented study is: NCT01970995
* Levels of Biomarkers Detected (Three-Month Study in Japan)

3. Exposure response

Clinical findings indicate that switching to IQOS can have a positive impact on smokers’ health risk.


In a six-month clinical study complemented with a six-month extension, we measured clinical risk markers known to be affected by smoking, and reversed upon cessation.


We observed that after switching from smoking to IQOS for six months, all these indicators changed in the same direction as expected upon smoking cessation based on the literature, five of them with statistical significance. The data from the second six months of the study are currently being analyzed.

Lüdicke, F., et al. (2019). Effects of Switching to a Heat-Not-Burn Tobacco Product on Biologically-Relevant Biomarkers to assess a Candidate Modified Risk Tobacco Product: A Randomized Trial. Cancer Epidemiol Biomarkers Prev July 3 2019 DOI: 10.1158/1055-9965.EPI-18-0915. (Reference)
The ID of the presented study is: NCT02396381.