Sensory Effects of Menthol and Nicotine in an E-Cigarette

Abstract

Introduction: Despite the longstanding use and popularity of menthol as a flavorant in tobacco products, its sensory interactions with inhaled nicotine have never been measured independently of the other irritants in tobacco smoke. We therefore measured the perception of menthol in an E-cigarette with the primary goal of assessing its analgesic effect on the sensory irritation produced by inhaled nicotine. Methods: Adult cigarette smokers sampled aerosolized E-liquids containing five different concentrations of nicotine with 0%, 0.5%, or 3.5% l-menthol, as well as two commercial menthol flavors with and without nicotine. For each of the E-liquids participants used a labeled magnitude scale to rate the Overall Sensation intensity, Coolness/Cold, and Irritation/Harshness they experienced, and a Labeled Hedonic Scale to indicate how much they liked/disliked the overall flavor. Results: The main findings were that (1) perceived Irritation/Harshness was unaffected by a low (0.5%) menthol concentration, whereas a high menthol concentration (3.5%) led to higher perceived Irritation/Harshness at low nicotine concentrations but to lower Irritation/Harshness at the highest nicotine concentration (24 mg/ml); (2) a commercial Menthol-Mint flavor produced similar results; (3) nicotine tended to enhance rather than suppress sensations of Coolness/Cold; and (4) menthol tended to slightly increase liking independently of nicotine concentration. Conclusion: In addition to adding a sensation of coolness, menthol can reduce perceived airway irritation and harshness produced by inhalation when nicotine concentration is high, and contributes to the sensory impact of E-liquids when nicotine concentration is low. Implications: The evidence presented here indicates that menthol can potentially improve the appeal of E-cigarettes not only via its coolness and minty flavor, but also by reducing the harshness from high concentrations of nicotine. As the first direct demonstration of an analgesic effect of menthol on inhaled nicotine in humans, these data also have implications for the role of menthol flavors in other inhaled tobacco products.

Plasma Menthol Glucuronide as a Biomarker of Acute Menthol Inhalation

“…The doses of menthol selected were derived from a published dose-finding study employing solutions from the same source. 18 The high menthol dose produced a cooling effect comparable to that of a commercial solution (AmericaneLiquidStore™) of comparable concentration; the lower dose produced a minimally discernable effect when inhaled from a nicotine free solution. Commercial suppliers of e-cigarette solutions rarely indicate menthol concentrations.…”

Role of sweet and other flavours in liking and disliking of electronic cigarettes

“…It is well established that menthol produces a cooling sensation along with a minty flavour 27. Previous studies have demonstrated that menthol has the effect of masking bitter taste and reducing harshness/irritation of cigarette smoke and nicotine 16 28–33. Furthermore, menthol tends to increase liking 16.…”

“…Previous studies have demonstrated that menthol has the effect of masking bitter taste and reducing harshness/irritation of cigarette smoke and nicotine 16 28–33. Furthermore, menthol tends to increase liking 16. The improved sensory appeal of menthol cigarettes is greatest for youth, women and African-Americans,30 33–35 and the positive associations of menthol flavour in e-cigarettes demonstrated in this study suggest that these subpopulations may be at risk for greater rates of e-cigarette initiation and use.…”

“…This is in contrast to previous studies,10 14 15 which used survey techniques to examine the relationship between perceived sweetness of e-cigarette and its usage. Recent work by Rosbrook and Green16 illustrates the effectiveness of the psychophysical approach in demonstrating sensory effects of menthol and nicotine in e-cigarettes. In the present research, we applied a similar approach to investigate the role of flavours in hedonic responses to e-cigarettes in an adult population.…”

Effect of Flavors and Modified Risk Messages on E-cigarette Abuse Liability

“…14,15 Menthol flavoring may increase e-cigarettes’ appeal, particularly at high nicotine concentrations. 16 Young adult cigarette smokers respond more to e-cigarette flavor availability than do older smokers, suggesting a role for flavors in attracting youth. 17 However, otherwise, there is a dearth of experimental research addressing how e-cigarette flavor affects e-cigarette use or abuse liability.…”