It’s True, but Still Harmful: Examining the Effects of Overgeneralized Health Messages by Social Media Influencers Using Two Pre-Registered Experiments

Social media influencers (SMIs) increasingly serve as role models for young people, shaping their health-related attitudes and behavioral intentions. In two pre-registered online experiments with Gen Z participants (total <i>N</i> = 1,548; age 16-27), we investigated how different message types by non-expert SMIs influence belief accuracy and intentions toward harmful health behaviors. Using a 3 × 2 between-subjects design, we manipulated the type of message (misinformation, overgeneralized, or correct) and the type of the SMI (famous or fictitious), with health literacy as a moderator. Our findings showed that both misinformation and overgeneralized health messaging (OHM) led to equally detrimental outcomes across various health contexts, undermining belief accuracy and encouraging harmful behavioral intentions. Furthermore, the familiarity of the SMI had minimal impact on the susceptibility to misleading health content. Also, the moderating effect of health literacy was limited. These results highlight the need for more research on the influence of SMIs and OHM on public health.