Synthetic cooling ingredients in e-cigarettes, such as WS-3 and WS-23, are linked to abnormal heart rhythms and increased cardiovascular stress, according to a study published in the journal Circulation: Arrhythmia and Electrophysiology. Research conducted on mice and human heart cells indicates these agents may heighten the risk of sudden cardiac arrest by disrupting electrical heart signals, prompting calls for stricter regulatory oversight of non-nicotine vape additives.
Why Cooling Agents Are Raising Health Concerns
Cooling agents are increasingly popular in the vaping industry because they create a smooth, chilling sensation without the harshness of traditional tobacco or the distinct taste of characterizing flavors. According to Dr. Alex Carll, principal investigator and associate professor of physiology at the University of Louisville School of Medicine, these synthetic coolants—specifically WS-3 and WS-23—often fall outside current FDA restrictions because they are not technically classified as "flavors."
While the FDA restricts many sweet or fruity flavors to discourage youth use, the prevalence of cooling-only additives has surged. Data from the CDC Foundation and Truth Initiative shows that sales of e-cigarettes containing synthetic cooling ingredients grew by 872.1% between 2020 and 2023.
Did you know?
Cooling agents are often added to e-liquids at higher concentrations than nicotine itself, yet they currently face fewer regulatory hurdles than traditional flavorings.
How Vaping Affects Heart Rhythm
The study found that cooling agents can trigger "premature heartbeats," which effectively triple in frequency when WS-23 is present in the aerosol compared to nicotine-only solutions. According to researchers, these coolants cause the heart to become electrically "ready" for a beat at the wrong time, leading to irregular heart rhythms.
In lab-grown human heart cells, the impact was even more pronounced when the cells were under hormonal stress. The coolants caused the cells to slow their rhythm while simultaneously accelerating the electrical recharge time between beats. This specific combination of factors is a known precursor to cardiac arrhythmias and, in severe cases, sudden cardiac arrest.
Comparing Traditional Flavors vs. Synthetic Coolants
Researchers noted a distinct difference in how various vape additives affect the cardiovascular system. According to the study, tobacco-flavored vapes generally caused less disruption to cardiac conduction in mice compared to those containing menthol or synthetic coolants.
| Additive Type | Observed Cardiac Impact |
|---|---|
| Tobacco Flavor | Minimal disruption to cardiac conduction |
| Menthol | Higher disruption than tobacco flavors |
| Synthetic Coolants (WS-3/WS-23) | Highest disruption; tripled premature heartbeats |
Source: Circulation: Arrhythmia and Electrophysiology (2026).
What This Means for Future Regulation
The medical community is calling for a closer look at how the FDA authorizes vape products. Dr. Jason J. Rose, chief of pulmonary, critical care & sleep medicine at the University of Maryland School of Medicine, noted that while the FDA evaluates manufacturing quality, this does not equate to a product being "safe."
"We just don’t know the long-term impact of vaping," Dr. Rose stated. Because the current research focused on short-term exposure, there is a significant data gap regarding how these coolants affect individuals with pre-existing conditions like hypertension, diabetes, or heart disease. Experts suggest that future policy may need to shift from regulating "flavors" to regulating all chemical additives that alter the biological response to inhalation.
Frequently Asked Questions
Are FDA-authorized vapes safe for my heart?
No. According to Dr. Jason J. Rose, FDA authorization generally assesses manufacturing standards and risk profiles similar to other tobacco products, which are already known to carry significant cardiovascular and pulmonary health risks.
Do cooling agents make nicotine more addictive?
The study found that cooling agents did not significantly increase the amount of nicotine absorbed into the bloodstream in mice, though researchers noted that more data is needed to confirm this in humans.
Could these coolants cause a heart attack?
The research indicates that cooling agents increase the risk of "mistimed" heartbeats and electrical disruption, which are known triggers for arrhythmias that can lead to sudden cardiac arrest.
Pro Tip: If you or a family member are concerned about the health effects of vaping, consult a primary care physician about smoking cessation programs that do not rely on e-cigarette alternatives.
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