RT Journal Article SR Electronic T1 Flavour chemicals, synthetic coolants and pulegone in popular mint-flavoured and menthol-flavoured e-cigarettes JF Tobacco Control JO Tob Control FD BMJ Publishing Group Ltd SP e3 OP e9 DO 10.1136/tobaccocontrol-2021-056582 VO 31 IS e1 A1 Omaiye, Esther E A1 Luo, Wentai A1 McWhirter, Kevin J A1 Pankow, James F A1 Talbot, Prue YR 2022 UL http://tobaccocontrol.bmj.com/content/31/e1/e3.abstract AB Background The Food and Drug Administration (FDA) has recently banned flavours from pod-style electronic cigarettes (e-cigarettes), except for menthol and tobacco. JUUL customers have quickly discovered that flavoured disposable e-cigarettes from other manufacturers, such as Puff, are readily available. Our goal was to compare flavour chemicals, synthetic coolants and pulegone in mint-flavoured/menthol-flavoured e-cigarettes from JUUL and Puff, evaluate the cytotoxicity of the coolants and perform a cancer risk assessment for pulegone, which is present in both JUUL pods and disposable Puff products.Methods Identification and quantification of chemicals were performed using gas chromatography/mass spectrometry. Cytotoxicity of the coolants was evaluated with BEAS-2B cells using the MTT 3-(4,5-dimethylthiazol-2-yl)−2,5-diphenyltetrazolium bromide assay. The cancer risk of pulegone was calculated using the margin of exposure (MOE).Results Menthol was the dominant flavour chemical (>1 mg/mL) in all products from both manufacturers. Minor flavour chemicals (<1 mg/mL) differed in the JUUL and Puff fluids and may produce flavour accents. The concentrations of WS-3 and WS-23 were higher in Puff than in JUUL. WS-23 was cytotoxic in the MTT assay at concentrations 90 times lower than concentrations in Puff fluids. The risk of cancer (MOE<10 000) was greater for mint than for menthol products and greater for Puff than for JUUL.Conclusions Switching from flavoured JUUL to Puff e-cigarettes may expose users to increased harm due to the higher levels of WS-23 and pulegone in Puff products. Cancer risk may be reduced in e-cigarettes by using pure menthol rather than mint oils to produce minty-flavoured e-cigarette products.All data relevant to the study are included in the article or uploaded as supplementary information. All relevant data are included in the submitted manuscript.