New research is raising serious concerns about an ingredient many vapers barely give a second thought: the cooling agents responsible for that familiar icy sensation in popular “ice” flavour e-cigarettes. Scientists are now finding that vape cooling agents may do far more than trick the mouth into feeling a chill. They could be putting real strain on the heart and circulatory system.

The Science Behind the Sensation

The refreshing “cooling” effect found in mint, menthol, and an expanding range of fruit and confectionery vapes is not caused by actual cold air. It comes from compounds such as menthol, WS-3, and WS-23, which activate a receptor in the body called TRPM8. Known as the body’s cold sensor, TRPM8 responds to these vape cooling agents as though temperature has genuinely dropped, even though the inhaled aerosol is no warmer or cooler than any other.

This sensory illusion has a practical effect on the vaping experience. The throat feels smoother, irritation is reduced, and users may inhale more deeply and more often as a result. What was assumed to be a harmless flavour trick is now looking rather more significant.

Heart Rate, Blood Pressure, and Irregular Beats

TRPM8 receptors are not confined to the mouth and throat. They are distributed throughout the body, including in the cardiovascular system. A study published in the Journal of the American Heart Association examined what happens when mice are exposed to menthol-containing e-cigarette aerosols. The findings were troubling.

The animals showed increases in both heart rate and blood pressure following exposure to the e-cigarette flavouring chemicals. More concerning still, researchers recorded a rise in ventricular premature beats, a form of irregular heartbeat that, while often described as harmless in isolation, is considered a marker of stress on the heart’s electrical system.

The study also detected elevated levels of epinephrine, the hormone produced during a fight-or-flight stress response. Crucially, some of these cardiovascular changes did not reverse quickly once exposure ended. Disruptions to heart rhythm regulation remained measurable weeks after the experiment concluded. That persistence distinguishes these findings from a simple, short-term physiological reaction.

Blood Vessel Damage: A Wider Cardiovascular Risk

The concern does not stop at the heart itself. Researchers have turned their attention to the blood vessels, specifically the endothelial cells that line their inner walls. These cells regulate blood flow, inflammation, and clotting. Laboratory studies have found that e-cigarette flavouring chemicals can damage endothelial cells, increasing inflammation, inducing cellular stress, and raising the likelihood of cell death. Some of these damaging effects occurred even in the absence of nicotine.

This finding carries particular weight because endothelial cell damage is widely recognised as one of the earliest detectable indicators of cardiovascular disease. If vape cooling agents are compromising these cells, the implications extend well beyond an occasional irregular heartbeat. Researchers are now treating this as a potential gateway to broader, longer-term heart and circulatory disease.

A Market Running Ahead of the Evidence

The regulatory picture has not kept pace with the science. Manufacturers have increasingly moved away from traditional menthol toward purely synthetic e-cigarette flavouring chemicals such as WS-3 and WS-23. These compounds produce an intense cooling sensation without any minty flavour, which means they can be blended invisibly into fruit, candy, and drink-inspired vapes. As of 2024, menthol and “ice” flavours accounted for a substantial share of the global e-cigarette market, with some surveys indicating they are among the most popular choices for young adult users.

The critical problem is that being safe to eat does not make a substance safe to inhale. Chemicals absorbed through the lungs enter the bloodstream far more rapidly and directly than those consumed in food. Regulatory frameworks for flavour safety typically assess oral ingestion, not pulmonary absorption. New formulations routinely reach the market long before comprehensive inhalation studies are completed.

What This Means

No researcher is claiming that a cooling agent in a vape will definitively cause a heart attack. The mouse studies need to be replicated in humans at scale before that kind of causal conclusion can be drawn. But the picture that is emerging challenges the assumption, long held in parts of the vaping industry, that flavouring chemicals are biologically inert bystanders.

Vape cooling agents that once seemed like a minor cosmetic feature of the product are now at the centre of a serious scientific conversation about cardiovascular safety. The body responds to these compounds. The heart responds. The blood vessels respond. That evidence is accumulating, and it deserves to be taken seriously.

Source: dbrecoveryresources