For years, researchers and regulators paid little attention to vaping cooling agents. Nicotine dominated the debate: how addictive, how fast-acting, how dangerous over time. But a quieter body of evidence has been growing in scientific journals, and it points to the flavouring compounds that give e-cigarettes that smooth, icy sensation. Scientists now want to know what those compounds do inside the human body, far beyond the mouth and throat.

What Are Vaping Cooling Agents?

The icy sensation in popular vape flavours does not happen by accident. Manufacturers engineer it deliberately.

Menthol has long featured in tobacco and nicotine products to deliver that familiar cool feeling. Increasingly, though, producers have shifted towards synthetic alternatives such as WS-3 and WS-23. These compounds produce an even more intense chill without any minty taste, which means fruit, candy and drink-flavoured vapes can carry the same icy hit. That makes them attractive to users who dislike mint but still want the cooling effect.

Here is the key point: these vaping cooling agents do not actually lower the temperature of the inhaled aerosol. Instead, they activate a receptor called TRPM8, the body’s dedicated cold sensor, tricking the brain into registering cold even though the air temperature stays the same. The result makes vaping feel smoother and less harsh, and researchers believe that encourages users to inhale more deeply and reach for their device more often.

How E-Cigarette Flavouring Chemicals Affect the Heart

Scientists long assumed these compounds acted only within the sensory system. Switch on the cold receptor, produce a pleasant feeling, nothing more. But TRPM8 receptors exist throughout the body, including in the cardiovascular system, and that changes the picture considerably.

A recent study on mice, published in a leading American heart journal, found that menthol-containing e-cigarette aerosols raised both heart rate and blood pressure. Researchers also recorded a higher occurrence of ventricular premature beats, a type of irregular heartbeat that can signal stress on the heart’s electrical system. On top of that, the mice showed elevated epinephrine levels, the hormone the body releases during a fight-or-flight response.

Some of those effects persisted after exposure ended. Scientists detected changes in heart rhythm regulation weeks after the mice stopped inhaling the aerosol. That is not a minor detail.

According to the World Health Organisation, cardiovascular disease already accounts for around 17.9 million deaths globally each year. Researchers studying vaping cooling agents are asking whether these compounds contribute to that burden in ways nobody has measured yet.

The Blood Vessel Problem

Beyond the heart, scientists are now examining what vaping cooling agents do to the blood vessels themselves.

Blood vessels carry a thin lining of cells called the endothelium. These cells regulate blood flow, suppress inflammation and control clotting. Laboratory studies show that certain e-cigarette flavouring chemicals damage these endothelial cells, drive up inflammation and trigger forms of cellular stress that make the cells more likely to die early. Notably, some of these effects appear even without nicotine present, which means the flavouring compounds themselves carry the risk.

Scientists regard endothelial damage as one of the earliest signs of cardiovascular disease. The harm here is not abstract. Researchers link these cellular changes to the same pathway that eventually produces heart attacks, strokes and circulatory disease.

A Booming Market With Too Few Answers

The scale of the problem matters.

Around 4.5 million adults in the United Kingdom currently vape, according to Action on Smoking and Health. Ice and cooling flavours rank among the most popular product categories, especially among younger users. Globally, the e-cigarette market exceeded $22 billion in 2023 and continues to grow rapidly.

Yet manufacturers have introduced many synthetic vaping cooling agents without long-term inhalation safety data. Regulators approve these compounds for food use, but the mouth and stomach absorb substances very differently from the lungs. The lungs deliver chemicals directly into the bloodstream at speed, and frameworks governing inhalable flavourings have not kept pace with the rate at which new products reach shelves.

New compounds can sit in millions of lungs long before scientists complete comprehensive studies.

What the Evidence Does and Does Not Tell Us

The research so far involves animal models and laboratory cell cultures, not large-scale human trials. No scientist currently argues that vaping cooling agents have proved they cause heart disease in people.

What researchers do argue is that these compounds are biologically active. The idea that e-cigarette flavouring chemicals sit passively in a product, doing nothing but improving taste, no longer holds up to scrutiny.

Vaping cooling agents interact with receptors, lift hormone levels, disrupt heart rhythms and stress the cells lining blood vessels. Researchers studying these effects describe a picture that is more complex than anyone initially expected, and one that calls for urgent investigation.

A Risk Factor Hiding in Plain Sight

Vaping’s story has always been shaped by what scientists did not yet know. Early assurances of safety gave way to evidence of respiratory harm. Now the cardiovascular picture demands the same honest reckoning.

Manufacturers added cooling agents in e-cigarettes as a selling point. Smoother. Less harsh. More enjoyable. That appeal is now the subject of the most serious scrutiny these products have faced outside of nicotine research.

If vaping cooling agents make inhalation feel effortless while simultaneously stressing the heart and damaging blood vessels, they stop being a feature. They become a risk that users deserve to understand clearly, and regulators can no longer afford to overlook.

Source: sciencealert