Can Established Vapers Distinguish Different PG:VG Ratios? A Pilot Study.

Objectives: Using the triangle test, this study explores whether established vapers can distinguish small differences between e-liquid propylene glycol: vegetable glycerin (PG:VG) ratios at fixed levels of nicotine and flavor, in order to examine the extent to which solvent ratios affects sensory experiences.

Methods: Watermelon flavored e-liquids (16mg/mL nicotine) used for this study differed in the ratio of PG:VG (30:70, 50:50; 70:30). Current vapers were randomized to one of 3 possible study conditions differing by PG:VG ratio. Participants sampled products following the triangle test, which presents 3 blinded products, 2 of which are identical. They were asked to identify and rate the 'odd' product.

Results: Of the 14 participants who completed the study, 34.9% were able to determine the 'odd' product. Ratings on the subjective response scales for the 'odd' product were quite low. Aversion scores differed significantly by correct identification of the 'odd' product (p = .045).

Conclusions: Established vapers in this study were unable to consistently distinguish PG:VG ratios, even for relatively large differences, and correct identification inconsistently related to subjective effects ratings. These preliminary findings suggest that the PG:VG ratio may not be a salient feature of vaping.