Introduction: Peer-to-peer sharing of personal health data on social media is increasingly used as a strategy to support public health goals. Such sharing is often assumed to motivate individuals to adopt or maintain healthy behaviors. However, the social and ethical implications of sharing-based interventions remain insufficiently examined. This paper offers an empirical and theoretical contribution by foregrounding the socio-technical contexts of sharing and analyzing how sharing-based interventions may drive social change. Building on these insights, it also outlines ethical considerations for researchers and stakeholders.

Method: We conducted 22 semi-structured interviews with participants in a regional public health intervention in Sweden. Interviews focused on participants' experiences of receiving personal health data and their reflections on sharing such data on social media. Analysis was guided by reflexive thematic analysis and informed by theoretical perspectives on the socio-technical embeddedness of health data and sharing practices.

Results: Participants understood health data as both personal and communal. Although many expressed discomfort with disclosing sensitive health information online, the peer-to-peer sharing model fostered a perceived moral obligation to share data for collective benefit.

Discussion: The tension between personal boundaries and perceived communal obligations raises important ethical concerns, particularly when individuals feel pressured to share data they would prefer to keep private. Our findings underscore the need for ethical frameworks that address social pressures, consent, and the emotional dimensions of data sharing. To support sustainable and ethical public health practices, further qualitative research is essential-particularly to understand how individuals navigate obligations and risks in technology-mediated care, and how these dynamics shape values such as autonomy, well-being, and collective responsibility.