- Most laboratory studies using a popular vaping exposure system likely overheated vape aerosol, producing unrealistic toxin levels.
- Only 14 of 40 studies gave enough detail to reproduce how the aerosol was generated.
- Many ran a high-power device with very low airflow, conditions the authors say don’t reflect real-world vaping.
- Researchers call for clearer reporting and better airflow so experiments match normal consumer use.
A new scientific review has raised concerns that dozens of laboratory studies may have overstated the risks of vaping because they used flawed testing conditions.
The paper, Critical appraisal of exposure studies on e-cigarette aerosols generated by high-powered devices, by Sébastien Soulet and Roberto Sussman, examined 40 published studies that used the InExpose system (made by SCIREQ®) to generate vape aerosol for experiments on cells or animals.
The study has been accepted for publication in Contributions to Research on Tobacco and Nicotina and will appear in the November issue.
The InExpose setup often uses a Joyetech EVIC Mini, a high-powered third-generation vaping device, with a custom 70 mL tank and a 0.15-ohm coil.
Soulet and Sussman found that this configuration was typically run at high power but with very low airflow – a combination that pushes the device into overheating, producing aerosols that real-world vapers would actively avoid.
“Only 14 out of the 40 studies provided sufficient information on their aerosol generation methodology,” the authors reported, calling the rest “unreproducible” because key parameters such as power, airflow, and voltage were not described.
Overheating conditions skew toxicity
The authors conducted their own calibration tests using the same equipment and compared those results with what previous studies reported. Their findings show that when the airflow is restricted to around one to two litres per minute (the default in many lab setups), the EVIC Mini’s “optimal regime” – where vapourisation is efficient and clean – ends at about 30 watts.
Above that level, the device enters an “overheating regime”, which produces far more harmful byproducts such as aldehydes and carbon monoxide.
Despite this, most studies reviewed effectively operated the device at 40 to 46 watts under the same low airflow, conditions that are well beyond what consumers would experience.
“There is full certainty that all 14 studies exposed biological systems to aerosols generated under overheating and unrealistic conditions with high aldehyde loads,” the authors wrote.
They also noted that because the remaining 26 studies used the same equipment but failed to describe their setups, it is very likely that their results were affected in the same way.
Why airflow matters
High-powered, “sub-ohm” vaping devices like the EVIC Mini are designed for direct-to-lung inhalation. In other words, large, airy puffs that bring plenty of air across the coil to cool it down.
In real-world use, airflow is around 10 litres per minute, not one or two. When the same device is tested in the lab with restricted airflow, the coil overheats, liquid burns, and toxic byproducts surge.
Under realistic airflow, the same device would operate smoothly and efficiently, producing far fewer harmful compounds. “At high airflows compatible with consumer usage, these conditions would not occur,” the authors conclude.
Unrealistic nicotine levels
The review also highlights another problem, of unrealistically high nicotine concentrations. Several studies used liquids containing 30 to 50 milligrams of nicotine per millilitre in high-powered tanks.
Such concentrations are typically used only with low-power pod systems that use nicotine salts, not with large, high-wattage devices that deliver much bigger puffs. In the lab, using those high strengths in a powerful device can overexpose cells or animals, distorting toxicity results.
Results may overstate real-world risks
By overheating the device and using high nicotine levels, many studies may have produced aerosols that are far more toxic than those inhaled by vapers in normal conditions.
That doesn’t mean the studies are without value, but it does mean their results should be interpreted carefully. The review suggests that testing conditions, not the products themselves, may be driving the high toxicity results often cited in debates about vaping safety.
Call for better standards
Soulet and Sussman stress that the InExpose is a valuable scientific tool, but say clearer technical standards are needed. They recommend that labs:
- Calibrate devices to check that displayed power and temperature match measured values.
- Use higher airflow (around 10 L/min) for high-powered, low-resistance coils.
- Reduce power to below 30 watts when using limited airflow.
- Fully report all technical details including device, coil, voltage, power, temperature mode, puff pattern, airflow, and liquid composition.
The review concludes that many preclinical studies likely tested overheated vapour under unrealistic lab conditions, which can exaggerate risks compared with how people actually vape.
By improving airflow, calibration, and transparency, future research could offer a clearer and more accurate picture of vaping’s real-world effects, helping public health science keep pace with technology and consumer behaviour.
