IMPORTANCE: The US has implemented several regulatory measures to govern the sale and marketing of electronic nicotine delivery systems (ENDS). A nicotine warning statement requirement became effective in September 2018, the minimum legal age for tobacco and nicotine sales was raised to 21 years (Tobacco to 21 Act [T21]) in December 2019, and a January 2020 enforcement policy limited the sale of cartridge-based ENDS to only tobacco and menthol flavors. OBJECTIVE: To track the presence of the nicotine warning statement, youth appeals, and flavor cues in the advertisements of 3 ENDS brands with marketing authorization during the implementation of the US federal tobacco policies. DESIGN, SETTING, AND PARTICIPANTS: In this qualitative study, a content analysis was conducted on ENDS advertisements in the market from November 18, 2015, to June 26, 2022. All mobile, online display, outdoor, and print advertisements from the 3 US ENDS brands with marketing granted orders as of June 2022 were collected through Vivvix, a commercial advertisement intelligence company. Advertisements were excluded if they targeted businesses rather than consumers, contained display errors that were unretrievable, or were duplicates. Data analysis was completed in March 2024. EXPOSURE: The nicotine warning statement requirement, T21, and the flavor enforcement policy. MAIN OUTCOMES AND MEASURES: Nicotine warning statement compliance and presence of youth-appealing features (eg, young models, sports, and sex appeal) and nonmenthol, nontobacco flavor cues (eg, images of food, characterizing words like sweet or fruity) in ENDS advertisements before and after policy implementation. RESULTS: Of the 614 advertisements analyzed, the proportion containing the nicotine warning statement increased from 18 of 83 (21.7%) in the year preceding policy implementation to 147 of 152 (96.7%) in the subsequent year (χ21 = 144.5
P <
.001). The proportion of advertisements containing any youth-appealing features increased from 35 of 171 (20.5%) in the year before T21 to 64 of 143 (44.8%) in the year after T21 (χ21 = 21.28
P <
.001). There was no significant difference in flavor cues in the advertisements in the year before the flavor enforcement policy (30 of 161 [18.6%]) and those in the following year (38 of 149 [25.5%]) (χ21 = 2.13
P = .14). CONCLUSIONS AND RELEVANCE: This qualitative study found immediate compliance with nicotine warning statements but no significant reduction in use of flavor cues and an increase in youth-appealing features in the first year after regulatory measures. The findings suggest a need for continued close monitoring of youth appeals in ENDS advertisements on all platforms to inform potential policies and interventions that can be used to counter the reach, appeal, and impact of these advertisements.