Sales of “ice” e-cigarettes have been increasing rapidly, with US sales growing by more than 10 times from 2017 to 2021. In 2023 57.9% of US youth used ice e-cigarettes, often combined with other flavors (such as strawberry ice, frosted mint or tobacco ice). Ice e-cigarettes are being marketed around the world. The cooling effect is usually created by adding a synthetic cooling compound that stimulates cold receptors at the back of the mouth without affecting the taste receptors on the tongue or odor receptors in the nose.
These three sensations — cool (or hot), taste and odor — together comprise perceived flavor.
Cigarette companies are using these synthetic coolants in their “non-menthol” cigarettes in an effort to get around prohibitions on selling (menthol) flavored tobacco products in California and Massachusetts.
Alayna P Tackett and her colleagues recently published and important paper, Effects of ‘Ice’ flavoured e-cigarettes with synthetic cooling agent WS-23 or menthol on user-reported appeal and sensory attributes, that examines the effects of one of these cooling agents, WS-23, on people use use e-cigarettes, cigarettes and both (dual users). The found that WS-23 improved the user experience of vaping, regardless of the product’s base flavor, nicotine concentration what product the person used.
Adding WS-23 significantly improved appeal measures, including whether participants would use the product again. It also improved sensory attributes, including countering harshness, which could make ice-flavored e-cigarettes easier to inhale than standard e-cigarettes.
While adding menthol had some of these effects, WS-23 affected more variables and the effects were generally larger than menthol, suggesting that these synthetic cooling agents have more negative public health implications than even menthol.
The findings in this study helps explain not only the rapidly growing popularity of ice flavored tobacco products by also earlier findings that ice flavors were associated with vaping more days per month, vaping more times per day and greater nicotine dependence.
The “WS” in WS-23 (and other synthetic cooling agents, such as WS-3) stands for “Wilkinson Sword,” who developed these compounds to use in shaving cream.
This study is a very carefully done experiment in which adult participants were randomly given different e-liquids with different flavors, nicotine levels, type of nicotine (protonated or free base), and presence absence of menthol. Neither the participant nor the person conducting the experiment knew what specific combination was being given. This randomized double blind design is the strongest design because it avoids biases on the part of both the subject and experimenter. In addition, because all the subjects received all the different experimental combinations without knowing what they were receiving, the results do not depend on exposure to marketing.
The fact that these artificial coolants do not have a taste or odor, makes it important that laws and regulations limiting the sale of flavored tobacco products include all three components of flavor — taste, aroma, and cooling/heating — in their definitions. Fortunately, the FDA’s proposed rules eliminating menthol included this definition. Hopefully, the final rule will, too.
The authors point out that, “the European Tobacco Products Directive, which prescribes
restrictions that prohibit manufacturers from including additives that increase a product’s attractiveness or facilitate inhalation. Canadian regulatory policies, which prohibit most flavouring additives, could also apply the current findings.”
Here is the abstract:
Background This clinical experiment tested the effects of exposure to e-cigarettes with WS-23 or menthol cooling additives on user appeal and sensory attributes, and, secondarily, whether WS-23 effects generalised across base characterising flavour, nicotine concentration, or nicotine/tobacco product use status.
Methods In this within-participant double-blind experiment, adult tobacco/nicotine users administered standardised puffs of 18 different e-cigarette solutions in randomised sequences using a pod-style device. Each of three base characterising e-cigarette flavour solutions (‘bold tobacco’, ‘mango,’ ‘wintergreen’) in both 2% and 4% concentrations of nicotine benzoate salt were manipulated by adding either: (1) Menthol (0.5%), (2) WS-23 (0.75%) or (3) No cooling agent. After each administration, participants rated 3 appeal and 5 sensory attributes (0–100 scales).
Results Participants (n=84; M(SD)=38.6 (13.6) years old) were either exclusive e-cigarette (25.0%), cigarette (36.9%) or dual (38.1%) users. WS-23 versus no coolant products produced higher liking, willingness to use again, smoothness, and coolness and lower disliking, bitterness, and harshness ratings (|B|difference range: 4.8 to 20.1; ps<0.005). Menthol (vs no coolant) increased willingness to use again and reduced harshness and coolness (ps<0.05). Flavours with WS-23 (vs menthol) were rated as smoother, cooler and less harsh (ps<0.05). Coolant effects did not differ by base flavour, nicotine concentration, or tobacco use status.
Conclusions Adding synthetic coolant WS-23 to e-cigarettes appears to make the vaping user experience more appealing, regardless of characterising base flavour. Regulatory agencies should be aware that the manufacturing process of adding synthetic coolants may increase the attractiveness of various e-cigarette products.
The full citation is: Tackett AP, Han DH, Peraza N, Whaley RC, Mason T, Cahn R, Hong K, Pang R, Monterosso J, Page MK, Goniewicz ML, Leventhal AM. Effects of ‘Ice’ flavoured e-cigarettes with synthetic cooling agent WS-23 or menthol on user-reported appeal and sensory attributes. Tob Control. 2023 Nov 8:tc-2023-058125. doi: 10.1136/tc-2023-058125. Epub ahead of print. PMID: 37940405. It is available here.
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