Objective E-cigarettes have gained popularity, most recently with pod-style devices, such as JUUL. We examined changes in JUUL awareness, use, perceptions, nicotine content knowledge, number of days a pod lasts and exposure to JUUL retail advertising over a 6-month period in a cohort of young adults.

Methods In spring and fall 2018, 1836 young adults completed online surveys on tobacco use, including JUUL perceptions and use behaviours. Demographics, tobacco use and JUUL advertising exposure in spring 2018 were examined as predictors of current JUUL use in fall 2018.

Results Ever and current JUUL use doubled in 6 months (5.9% vs 12.7%, p<0.001; 1.6% vs 3.4%, p<0.001). The number of days a JUUL pod lasts significantly changed (p=0.049). Although there was an increase in those reporting JUUL has as much or more nicotine than a pack of cigarettes, 58% are ‘not sure’ of JUUL’s nicotine content. Exposure to JUUL’s advertising significantly increased (31.8% to 46.4%; p<0.001). In multivariable models, those perceiving JUUL as or more harmful than cigarettes, and former and never cigarette smokers had significantly lower odds of current JUUL use at 6 months compared with their respective counterparts (p<0.0001). Those reporting exposure to JUUL’s advertising had significantly increased odds of current JUUL use 6 months later (p<0.03).

Conclusions Findings demonstrate changes in knowledge of JUUL’s nicotine content, perceptions and use over a short period of time, suggesting frequent measurement is necessary. Additionally, efforts are needed to regulate retail advertising and ensure consumer education about product risks as they are associated with current use.