'Clear' E-Cigarettes Cause Greater Immediate Increases in Blood Pressure and Heart Rate

Recent research conducted by the Department of Chemical and Environmental Engineering at Yale University and Boston University Chobanian, Avedisian School of Medicine has revealed concerning effects of certain 'clear' e-cigarettes on cardiovascular health. The study found that these products induce more significant acute increases in blood pressure and heart rate compared to non-'clear' flavored e-cigarettes or even nonuse. Notably, 'clear' e-liquids often contain synthetic cooling agents like WS-23 and WS-3, alongside traditional flavorants such as menthol. These synthetic coolants mimic the cooling sensation of menthol but do not have a distinct odor, and their presence appears to contribute to heightened cardiovascular responses.

The investigation focused on disposable e-cigarettes sold in Massachusetts, especially after the state's ban on flavored tobacco products, which aimed to limit youth access to flavored e-cigarettes. The term 'clear' has been used as a workaround, lacking a specific regulatory definition, making these products appealing. Chemical analysis of 19 'clear' devices showed high levels of synthetic coolants, with WS-23 detected in all samples and WS-3 in most. Menthol was also prevalent, alongside various other flavorants, and nicotine concentrations varied from 28 to 53 mg/g.

In controlled exposure sessions involving participants aged 18–45, blood pressure and heart rate were measured before and after vaping. Results indicated that 'clear' e-cigarettes caused significantly greater increases in systolic and diastolic blood pressure, mean arterial pressure, and heart rate than non-'clear' flavored products or nonusers. These effects persisted even after adjusting for factors like age, sex, cigarette use, and puff number.

The findings suggest that the combination of synthetic coolants and traditional flavorants in 'clear' e-liquids may undermine the effectiveness of flavor bans intended to protect youth. The study emphasizes the need for regulatory vigilance concerning these unregulated additives, which could lead to more pronounced adverse cardiovascular effects.

Given the popularity of flavored e-cigarettes among young populations, understanding and regulating the chemical components of these products is critical for public health. Further research is necessary to explore long-term impacts, but current evidence points to the potential hazards of 'clear' e-cigarettes with synthetic cooling agents.

Source: https://medicalxpress.com/news/2025-08-cigarettes-linked-greater-acute-blood