• E-cigarette users who were in user-created groups had significantly more negative health-related outcomes than those who saw advertisements or followed brand pages.
  • Exposure to three types of e-cigarette marketing had a significant additive effect on health-related outcomes, compared with exposure to two or fewer types.
  • Social identification, attention to social comparison, and e-cigarette subjective norms moderated between exposure to e-cigarette marketing and health-related outcomes.
  • The results of this study also might apply to advertising of other health-related products on social networking sites, including over-the-counter pharmaceuticals and prescription drugs (e.g. opioids).