---

Background and Object: Strengthening healthy lifestyle adherence through self-care approach requires to consider information seeking behavior of audience. However, the popularity, facilities, and easy access to online resources have led to the dissemination and sharing inaccurate information, which is caused to more challenges in evaluating the accuracy of these messages. The present study tried to identify effectiveness components of health messages on Instagram.

Materials and Methods: The study conducted an experimental research design by intervention in the characteristics of the source (credibility/likeability), message framing (gain/loss), involvement (high/low) and social support (absent/present) among 442 participants. All intervention groups randomized and participants after exposure with one of the 16 Instagram posts answered questions regarding demographics, independent variables, acceptance, behavioral intention and sharing.  

Results: Analyzing data revealed that source credibility (b = 0.33), involvement (b = 0.25) and source likeability (b = 0.16), respectively have the greatest effect on message acceptance. Also, despite of non-significant difference between accepting the loss or gain frames (P = 0.08), the moderating effect of involvement levels (F (1, 438) = 6.04, p = 0.01, η2p = 0.014) confirms that participants with low involvement find the gain-framed message more convincing. In addition, the acceptance of the message could predict a positive relationship with behavioral intention (b = 0.52) and sharing (b = 0.45).

Conclusion: As a result, it is suggested that by planning effective communication strategies, along with the role of heuristic cues such as social support or source credibility in low involvement issues, tries to enhance the coordination between community health priorities and individuals’ health needs.