title: Sensory Effects of Menthol and Nicotine in an E-Cigarette.
abstract: 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.
  
  
  
  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.
  
  
  
  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 (24mg/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.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: The John B. Pierce Laboratory, New Haven, CT;
authors.forename: Kathryn
authors.initials: K
authors.lastname: Rosbrook
authors.affiliation: The John B. Pierce Laboratory, New Haven, CT; Department of Surgery (Otolaryngology), Yale School of Medicine, New Haven, CT green@jbpierce.org.
authors.forename: Barry G
authors.initials: BG
authors.lastname: Green
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D066300:Electronic Nicotine Delivery Systems; D005260:Female; D005421:Flavoring Agents / Q000494:pharmacology*; D006801:Humans; D007509:Irritants / Q000494:pharmacology*; D008297:Male; D008610:Menthol / Q000494:pharmacology*; D008875:Middle Aged; D009538:Nicotine / Q000494:pharmacology*; D012677:Sensation / Q000187:drug effects*; D013649:Taste / Q000187:drug effects; D055815:Young Adult
chemical_list: D005421:Flavoring Agents; D007509:Irritants; D008610:Menthol; D009538:Nicotine