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From cola or menthol to strawberry-kiwi: e-cigarette aromas appeal to young people inparticular. However, the substances pose health risks.
In contrast to “classic” cigarettes, no tobacco is burned in e-cigarettes. Instead, a liquid is heated and vaporised in the devices. The main ingredient of this liquid is usually propylene glycol, which is also used in fog machines. Together with glycerine, it functions as a nebulising agent and is responsible for the dense vapour from e-cigarettes.
The liquids also usually contain nicotine and numerous aromatic substances and fragrances. They give e-cigarettes a fruity, fresh, or sweet taste.
Studies indicate that heating the nebulising agents propylene glycol and glycerine can lead to the formation of carcinogenic substances known as aldehydes. It is well established that, on the one hand, nicotine is highly addictive, and on the other hand can disrupt brain development. This is demonstrated, for example, by reduced learning ability and increased anxiety.
“It is still unclear what effects many ingredients have on the body after inhalation,” says chemist Dr Elke Pieper, who examines the safety level of tobacco products and e-cigarettes at the German Federal Institute for Risk Assessment (BfRshort forGerman Federal Institute for Risk Assessment). This particularly applies to the aromatic substances and fragrances in e-cigarettes. “Individual liquids often contain a mixture of dozens of different aromatic substances and fragrances.”
Many of these substances have been tested and approved for use in foodstuffs and cosmetics. “Negative health effects are not to be expected in these cases. However, it’s another story altogether when a substance is heated and inhaled,” Pieper says.
Heat and contact with other ingredients can cause substances to change, and new, possibly harmful compounds may occur. One such example is the sweetener sucralose, which is permitted in the EU as a food additive. It does not pose a health risk when used in sugar-free lemonades, spreads, or jams. However, when sucralose is heated to 120 °Cshort fordegrees Celsius – as happens with e-cigarette liquids – chloropropanols arise, which can harm health.
Another problematic aromatic substance is menthol, which is found not only in e-cigarettes with an explicit “menthol taste”, but also in lower doses in many other liquids to round off the taste. A side effect which should not be underestimated is that menthol reduces the natural urge to cough, which is actually an important defence mechanism of the body.
“If the urge to cough is weakened by menthol, then substances from e-cigarettes that are harmful to health can be more easily and deeply inhaled,” Pieper says. “We assume that, even at lower dosages, menthol and similar aromatic substances in the liquids make it easier to start using e-cigarettes and make them more appealing to adolescents and young adults.” This is one reason why menthol in tobacco cigarettes has been banned in the EU since 2020.
Many questions about the health risks posed by e-cigarettes remain unanswered, particularly with respect to long-term effects. That is another reason why the BfRshort forGerman Federal Institute for Risk Assessment will continue to examine the issue.
“However, based on initial population group studies, particularly from the USA, we already know that the number of cardiovascular diseases among e-cigarette users has risen,” Pieper says. “In Germany, too, there have been repeated cases of severe pneumonia. No matter how tempting the vapour may smell, users are inhaling a chemical mixture containing many substances hazardous to health.”
