Cyberchondria refers to the compulsive behavior of excessively search for health-related information online, which can heighten anxiety about one’s health. While previous studies have identified numerous cognitive and emotional factors that contribute to cyberchondria, how individuals suffer from cyberchondria when they face complicated online system features warrants further investigation. This study introduces a moderated mediation model to explore the relationships between online system complexity, health advertising intrusiveness, health risk perception, health information skepticism and cyberchondria. Drawing on data from an online survey of 437 participants, the results indicate that system complexity is positively related to cyberchondria through health advertising intrusiveness and risk perception. Additionally, health information skepticism negatively moderates the effect of system complexity on health advertising intrusiveness. This study concludes with a discussion of its implications and limitations.