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Ice flavours and non-menthol synthetic cooling agents in e-cigarette products: a review
  1. Adam M Leventhal1,
  2. Alayna P Tackett2,
  3. Lauren Whitted2,
  4. Sven Eric Jordt3,4,
  5. Sairam V Jabba3
  1. 1 Institute for Addiction Science, University of Southern California, Los Angeles, California, USA
  2. 2 Department of Preventive Medicine, Keck School of Medicine University of Southern California, Los Angeles, California, USA
  3. 3 Anesthesiology, Duke University School of Medicine, Durham, North Carolina, USA
  4. 4 Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
  1. Correspondence to Dr Adam M Leventhal, University of Southern California, Los Angeles, USA; adam.leventhal{at}


E-cigarettes with cooling flavours have diversified in ways that complicate tobacco control with the emergence of: (1) Ice-hybrid flavours (eg, ‘Raspberry Ice’) that combine cooling and fruity/sweet properties; and (2) Products containing non-menthol synthetic cooling agents (eg, Wilkinson Sword (WS), WS-3, WS-23 (termed ‘koolada’)). This paper reviews the background, chemistry, toxicology, marketing, user perceptions, use prevalence and policy implications of e-cigarette products with ice-hybrid flavours or non-menthol coolants. Scientific literature search supplemented with industry-generated and user-generated information found: (a) The tobacco industry has developed products containing synthetic coolants since 1974, (b) WS-3 and WS-23 are detected in mass-manufactured e-cigarettes (eg, PuffBar); (c) While safe for limited oral ingestion, inhalational toxicology and health effects from daily synthetic coolant exposure are unknown and merit scientific inquiry and attention from regulatory agencies; (d) Ice-hybrid flavours are marketed with themes incorporating fruitiness and/or coolness (eg, snow-covered raspberries); (e) WS-23/WS-3 concentrates also are sold as do-it-yourself additives, (f) Pharmacology research and user-generated and industry-generated information provide a premise to hypothesise that e-cigarette products with ice flavours or non-menthol cooling agents generate pleasant cooling sensations that mask nicotine’s harshness while lacking certain aversive features of menthol-only products, (g) Adolescent and young adult use of e-cigarettes with ice-hybrid or other cooling flavours may be common and cross-sectionally associated with more frequent vaping and nicotine dependence in convenience samples. Evidence gaps in the epidemiology, toxicology, health effects and smoking cessation-promoting potential of using these products exist. E-cigarettes with ice flavours or synthetic coolants merit scientific and regulatory attention.

  • E-cigarettes
  • synthetic cooling agents
  • menthol
  • e-cigarette flavors

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  • AML and SVJ contributed equally.

  • Contributors AML created the idea for the article. AML, AML, SVJ, APT, SEJ, and LW contributed to the literature search. AML and SVJ developed major portions of the article text. APT and SEJ wrote subsections of the article. AML is the guarantor who accepts full responsibility for the finished article. All authors read drafts, provided critical feedback and edits, and approved the entire article.

  • Funding AML, LW, AT were supported by grant of the National Institutes of Health (NIH) and cooperative agreement U54CA180905(USC Tobacco Center of Regulatory Science) from the National Cancer Institute (NCI) and FDA Center for Tobacco Products (CTP). AML was also supported by National Institute on Drug Abuse (NIDA) grant K24DA048160. SVJ and SEJ were supported by grant R01ES029435 from the National Institute of Environmental Health Sciences (NIEHS) of the National Institutes of Health (NIH) and cooperative agreement U54DA036151 (Yale Tobacco Center of Regulatory Science) from the National Institute on Drug Abuse (NIDA) and FDA Center for Tobacco Products (CTP).

  • Competing interests Unrelated to the current research, SEJ reports receiving personal fees from the Research Institute for Fragrance Materials and non-financial support from GlaxoSmithKline Pharmaceuticals.

  • Provenance and peer review Not commissioned; externally peer reviewed.