If you’ve ever tried a tobacco product or been around someone who has, you might have heard of the “throat hit.” This is the sharp, sometimes intense feeling in the back of the throat when inhaling. For people who regularly use nicotine, that throat hit is often a familiar and sometimes a satisfying sensation. But for people who are new to nicotine, it can feel uncomfortable. Our research group set out to understand what influences throat hit in electronic nicotine delivery systems (ENDS). We found that it’s influenced by multiple factors—like device power, the ingredients in the e-liquid, and the way a person puffs on the device. With this knowledge, regulators may be able to make ENDS less appealing to people who haven’t used nicotine before, while still providing the familiar experience that current smokers look for.
What Causes the Throat Hit?
When someone inhales from an e-cigarette, they’re inhaling a warm aerosol (a mix of gases and particles) that flows from the device’s mouthpiece through their mouth and into their throat. This aerosol contains not only nicotine but also ingredients like propylene glycol (PG) and vegetable glycerin (VG), along with freebase or protonated nicotine. The throat hit is partly caused by nicotine absorption in the back of the throat. As the relatively warm aerosol enters the cool, humid environment of the throat (typically around 37.5°C and 100% humidity), temperature and moisture differences create conditions that drive the transfer of nicotine, PG, and VG from the aerosol into the airway walls. The deposition of nicotine on the upper airway walls generates a strong, sometimes harsh sensation in the throat. Our physics-based mathematical model model simulates each part of this journey: how the aerosol forms in the device, travels through the mouthpiece, and changes as it moves down the airway. We account for the heat and mass transfer happening continuously, allowing us to see how temperature, composition, and other factors affect throat hit. The figure below shows the various stages of our model. 
Testing Our Model Against Real Experiences
To validate our model, we tested it against real-life experiences. We asked participants to rate the intensity of the throat hit they felt under various ENDS settings. Our predictions from the model lined up well with these reports: when our model predicted high levels of nicotine deposition, participants reported a strong throat hit. This strong correlation confirmed that the settings we studied—device power, e-liquid ingredients, and puffing style—are indeed key factors in controlling throat hit.
Why These Findings Matter for Public Health
This research is important because it suggests that throat hit can be managed by changing specific ENDS settings. With this knowledge, we might be able to discourage people who don’t typically use nicotine from starting by adjusting the device to deliver a stronger throat hit—an experience likely to be uncomfortable for beginners. For regular smokers looking for an alternative, we can maintain settings that provide the familiar sensation they’re used to.
If you would like to know more about this study, please check out our article:
El Hourani, Mario, Alan Shihadeh, Soha Talih, and Thomas Eissenberg. 2022. ‘Comparison of nicotine emissions rate, ‘nicotine flux’, from heated, electronic and combustible tobacco products: data, trends and recommendations for regulation’, Tobacco Control: tobaccocontrol.