Health Influencers: Effects of Influencer Type and Expertise on Credibility, Trust, and Behavioral Intentions

Trust in the health sector has been declining, leading the public and organizations to turn to health influencers in their marketing strategies. As such, this study aims to investigate how patient and physician influencers, who are either generalists or specialists in chronic migraine, influence source credibility, trust in message, and purchase and sharing intentions. Guided by the social media influencer value model, we conducted a 2 (Influencer type: patient/physician) × 2 (Area of expertise: generalist/specialist) + 1 control between-subjects factorial experiment with a sample of 485 U.S. residents living with chronic or episodic migraine. We found that participants rated physician influencers as having higher levels of source expertise and rated both physician and patient influencers higher than the control on source authenticity. Specialist influencers were also rated as having higher source expertise compared to generalists and the control, but both specialist and generalist influencers were rated higher on source authenticity compared to the control. Expertise, similarity, and trustworthiness positively impacted sharing and purchase intentions. Trust in the message fully mediated the relationship between credibility components and both sharing and purchase intentions.