A new study has issued a health warning to vapers who choose fruity flavours, finding that these options are linked to significantly more changes in gene activity than sweet, mint, or menthol varieties. The research, published in Frontiers in Oncology, examined oral cell samples from 35 vapers, 24 smokers, and 24 non-users, using RNA sequencing to compare gene expression.
Fruity Flavours and Gene Activity
Regular vapers who used fruity flavours such as mango and watermelon showed altered activity in 3,124 genes across the genome compared to non-users. While the study does not prove that fruity vapes cause diseases, changes in gene activity are early biological signals linked to cancer, heart disease, immune disorders, and respiratory conditions. The researchers emphasised that vape flavours do not directly change the DNA sequence but significantly impact gene expression—how genes are activated or deactivated.
Ahmad Besaratinia, PhD, professor of research population and public health sciences at the Keck School of Medicine of USC and senior author, said: “The implication is that each flavour has unique attributes that produce different biological effects. This is something regulators should carefully consider when evaluating the health risks or potential benefits of each flavoured e-cigarette product.”
Comparison Across Flavours
The study found that fruit flavours were linked to changes in 970 of the affected genes (31%), compared to 92 genes for sweet flavours (2.9%) and 27 genes for mint or menthol (0.9%). The highest figure was seen among people using multiple flavours, linked to 2,009 affected genes (64.3%). Higher-generation devices, including mod-style products, were also associated with more gene expression changes than earlier-generation devices.
Broader Health Context
A separate 2026 systematic review in Frontiers in Public Health warned that fruity, menthol, mint, and sweet flavours have been linked to increased nicotine preference in animal models, inflammation, cellular damage, cardiovascular changes, and in human studies, respiratory symptoms, reduced lung function, and DNA damage in oral cells. However, much of the evidence remains early, mixed, or based on animal and laboratory models.
The NHS position remains that vaping exposes users to fewer toxins and at lower levels than smoking, but it is unlikely to be entirely harmless, and long-term effects are not yet fully known. The NHS advises adult smokers using vapes to quit tobacco to stick to legal, regulated products and avoid anything with unclear ingredients or non-compliant packaging.
Expert and Industry Response
Shane Margereson, who works with adult vape customers at Ecigone, said: “Adult smokers using vaping to move away from cigarettes should stick to reputable retailers, check product information carefully and avoid anything that looks like an unregulated import. Flavour choice is personal, but it should never come before compliance, ingredient transparency or official health advice. Vapes are for adult smokers, not children, under-18s or people who have never smoked.”
The authors of the Frontiers in Oncology study said the findings support looking at flavourings and device design when assessing biological effects of vaping products, rather than focusing solely on frequency or duration of use.
