Toxic chemicals accumulate in vapes as their juice runs low
Research published in ACS Omega 2026 indicates that high-puff-count vapes concentrate toxic aldehydes, specifically methylglyoxal (MGO) and glyoxal, as liquid levels drop. Prue Talbot of the University of California, Riverside, found these compounds in used devices, suggesting they form through the thermal decomposition of the carrier solution during the heating cycle of each puff.
Why do used vapes contain more toxic aldehydes?
The increase in toxic compounds stems from the chemical breakdown of the vape’s carrier solution during use. Prue Talbot and her team analyzed 77 devices across 20 different brands, comparing unused products to discarded and donated vapes.
The team detected nearly 200 chemical components. This included nine aldehydes that manufacturers had not listed. MGO and glyoxal were present at notably higher concentrations in every used device tested.
What is the risk of high-puff-count devices?
High-puff-count pens may increase user exposure to problematic compounds by concentrating toxicants over a longer period. As these devices run low on fluid, the aldehyde breakdown products become more concentrated in the remaining liquid.
The biological impact is immediate. In a lung cell assay, bronchial cells showed substantial cell rounding—a key marker of stress—after only nine puffs of MGO.
Which chemicals are inhaled during vaping?
Some of the most toxic components may not remain in the device at all. Donal O’Shea, an analytical chemist at the Royal College of Surgeons in Ireland, noted that the aldehyde acrolein was present in several unused brands and flavors.
However, acrolein decreased or vanished in almost all used e-cigarettes. O’Shea stated this is alarming because it suggests the toxic aldehyde is being produced during vaping and is entering the lungs.
What happens next in vape research?
Researchers may now shift toward more physiological studies. Havovi Chichger, a cell biologist at Anglia Ruskin University, suggests that whole organ studies could be a possible next step.
Chichger notes that the liquid remaining in the chamber differs from what a person actually inhales. Future studies may likely focus on determining the exact vapor composition that the lungs encounter.
Frequently Asked Questions
What are the primary toxic aldehydes found in used vapes?
The primary toxic aldehydes identified in higher concentrations in used devices are methylglyoxal (MGO) and glyoxal.
How does MGO affect lung cells?
A lung cell assay demonstrated that within nine puffs of MGO, bronchial cells exhibited substantial cell rounding, which is a marker of cell stress.
Why is the disappearance of acrolein in used vapes significant?
According to Donal O’Shea, because acrolein is present in unused devices but absent or reduced in used ones, it is likely being inhaled into the lungs during the vaping process.
Do you think manufacturers should be required to list all aldehydes produced during the heating process?