A widely used ‘ice’ vape flavour may be linked to harmful hidden effects, according to new research, with scientists saying these additives “should be considered for regulation”.
E-cigarette use remains widespread in the US. The latest federal data suggest about 7 percent of adults currently use e-cigarettes, up from 6.5 percent in 2023 and nearly double the level seen in 2020.
Use is especially common among younger adults. In 2024, nicotine vaping was reported by 23.7 percent of young adults aged 18 to 25, and adults aged 21 to 24 remained the age group most likely to vape.
As vaping becomes more common, researchers are continuing to examine the possible health consequences that may come with it, including the effects of flavourings and cooling agents that are added to many popular products.
A recent study has now zeroed in on one especially popular type of vape flavouring that could be creating additional concerns: synthetic coolants used in menthol and ‘ice’ products.
The study looked at chemicals responsible for the cooling sensation in vapes, which are commonly found in menthol and ‘ice’ products, including compounds such as WS-23 and WS-3.
These cooling ingredients are often favoured because they can make inhaling vapour feel less harsh and more comfortable. They are also widely used in products marketed as “ice”, “frost”, or “cool” flavours, which may make them especially appealing to younger users.
In the study, researchers carried out tests using mice as well as human heart cells in laboratory conditions, and found troubling responses to the chemicals.
The results indicated that the substances affected heart rate variability, meaning they altered the timing between beats, and also increased irregular heartbeats in the animals.
Researchers said that kind of disruption may increase the likelihood of serious cardiovascular problems, including raised blood pressure, a faster heart rate, rhythm disturbances, and potentially fatal cardiac arrest.
Study author Dr Alex Carll said: “Synthetic coolants create a chilling sensation without flavour so they fall outside of e-cigarette restrictions that focus on flavours.
“These findings suggest they could cause arrhythmias by making the heart electrically ready too soon or too late for the next beat.”
The expert added: “In general, we’ve seen tobacco-flavored vapes do not disrupt cardiac conduction in mice as much as vapes with either menthol or synthetic coolants.
“Coolants are added to e-cigarettes at very high levels so they should be considered for regulation.”
The findings add to wider concerns from health professionals about vaping, despite it often being promoted or viewed as a safer option than traditional cigarettes. Public health agencies continue to note that e-cigarettes are generally considered less harmful than smoking combustible tobacco, but not harmless, and they can expose users to nicotine, irritants, and other potentially toxic chemicals.
Health authorities have warned that vaping can be associated with throat and mouth irritation, coughing, headaches, nausea, and nicotine dependence, and that long-term effects are still being studied. Nicotine exposure is also a concern for adolescents and young adults because it can affect the developing brain.
GP and author Dr Philippa Kaye explained to The Sun: “In a nutshell, vaping is better than smoking, but breathing air is better than vaping at all.”