Ice flavours and non-menthol synthetic cooling agents in e-cigarette products: a review

Abstract

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.

Keywords: E-cigarettes; e-cigarette flavors; menthol; synthetic cooling agents.

Fig 1.. E-cigarette solutions marked in ice-hybrid flavors:

A. Ice Dragon (blueberry, dragonfruit, mint). B. Banana Ice (banana, menthol). C. Drops Ice (menthol, mint). D. Mixed Berry Ice (strawberry, blackberry, raspberry, blueberry, menthol), E. Black (Liquorish) Ice. See Table for additional description.

Fig 2.. Example disposable and pod-style e-cigarette products with ice-hybrid flavors:

A. Lush Ice (watermelon, menthol, raspberry). B. Guava Ice (guava, menthol). C. Lychee Ice (lychee, menthol). D. Tropical Ice (pineapple, orange, mango, mint), E. Iced Pineapple (JUUL compatible pod). See Table for additional description