IntroductionGiven that the US Food and Drug Administration (FDA) authorised reduced exposure messaging to be used in IQOS marketing, we examined: (1) IQOS ad content; (2) advertising media channels and (3) changes in advertising efforts over time.MethodsWe conducted a mixed-methods study regarding IQOS ad content (headlines, themes, images), ad occurrence characteristics (including content, media channels and adspend) in the USA from August 2019 to April 2021 using Numerator advertising/marketing data.ResultsAcross 24 unique ads and 591 occurrences (84.6% online, 8.0% print, 7.4% mobile), there was $4 902 110 total adspend (98.9% allocated to print). Across unique ads, occurrences and adspend, prominent themes included ‘real tobacco’ (45.8%, 47.4%, 30.1%, respectively), less odour/ash (29.2%, 21.0%, 29.9%) and switching from cigarettes (25.0%, 19.5%, 69.4%), and images mainly featured the product alone (58.2%, 61.4%, 99.5%) or with women (25.0%, 19.1%, 0.3%). Per occurrences and adspend, the most prominent media channel themes (eg, magazine/website topics) were technology (19.3%, 10.6%), women’s fashion (18.1%, 26.2%), weather/news (9.0%, 15.3%) and entertainment/pop culture/gaming (8.5%, 23.1%). Ad themes appearing only post-FDA authorisation included switching from traditional cigarettes, same-day/home-delivery, convenience (eg, use indoors), reduced exposure to some dangerous substances, science/research and distinction from e-cigarettes. Overall adspend per occurrence increased postauthorisation (p=0.016); the highest adspend per unique ad (69.3% of total) focused on ads featuring reduced exposure.ConclusionsRegulatory efforts must be informed by ongoing surveillance of IQOS marketing efforts and its impacts, particularly how specific consumer subgroups (eg, tobacco non-users, women, young people) are impacted by marketing exposure.