Flavors make ecigs attractive to young people and can promote their use, especially in non-smoking adolescents. They can also trigger chemical reactions between vaporised flavouring chemicals and propylene glycol, the main substance in vaping liquids, to produce toxic compounds that may damage users’ lungs.

Research suggests that the extensive landscape of e-cig flavours is an important factor for initiation and escalation of e-cigarette use among youth, especially in those who have never smoked [1-4]. The availability of many fruit, sweet, and cooling flavours – found both in blended flavours that may include names describing these characteristics and concept flavours that do not – could be particularly appealing to young people.

A World of Flavors: Understanding Ecig Flavours

The study used a machine-learning approach to classify e-liquids into the 16 main categories of a flavour wheel using flavour-related information submitted by manufacturers. Using this method, we were able to classify the majority of the products (79%) into one of the categories of the flavour wheel. The remaining 15% were classified as other flavours. These included flower- and plant-related flavours (flower, cherry blossom, roses, violet, hibiscus, verbena, woodruff); vegetable-related flavours (cucumber, rhubarb); as well as jam and cannabis flavours.

The large number of other flavours can be attributed to the popularity of ‘homemade’ e-liquid mixes. This is an unregulated form of vaping that involves mixing e-liquids with nicotine concentrates purchased from online retailers. These ‘nicotine boosters’ are often sold in fruity, sweet or cooling flavours and can introduce chemicals that have not been tested for safety into the user’s lungs.