Abstract
BACKGROUND: Adolescents are increasingly exposed to online health information promoting supplements as quick solutions for weight management and muscle development, raising public health concerns. OBJECTIVE: This study investigated whether online media engagement-weight-and fitness-related information-seeking behaviors and the internalization of online appearance ideals-predicts adolescents' online purchasing of weight-loss and muscle-building products, with attention to differences between girls and boys. METHODS: A cross-sectional online survey was conducted among 1,526 Czech adolescents (50% girls) aged 13-18 years (M = 15.4, SD = 1.7). Measures included self-reported online weight- and fitness-related information-seeking behaviors, internalization of online appearance ideals (thin-ideal among girls; muscular ideal among boys), and online purchasing of weight-loss and muscle-building products. Hierarchical regression analyses were conducted separately for girls and boys, controlling for sociodemographic and body image variables. RESULTS: Overall, 4.1% (63/1,521) purchased weight-loss and 19.1% (303/1,524) purchased muscle-building products online. For both girls and boys, greater engagement in seeking weight- and fitness-related information was associated with purchasing both product types. Internalization of online appearance ideals was significantly associated with muscle-building but not weight-loss product purchases. CONCLUSION: Findings highlight a novel pathway through which online media may shape youth consumer choices, pointing to the need for media literacy and body image-informed strategies to promote safer decision-making.