Background The provision of medical services by Medical Teams (MT) on Online Healthcare Communities (OHCs) is a novel method employed by geographically-dispersed healthcare professionals to serve one patient simultaneously, allowing patients to receive more specific, targeted and comprehensive advice. As a relatively new method of service delivery, little attention has been paid to identifying the determinants of Team-based Service Demands (TSD). Based on Upper Echelons Theory and Social Exchange Theory, this study examines the impact of both professional capital ( status capital and decisional capital ) and team heterogeneity ( team size and dispersion ) on TSD. Methods This study uses data collected from 890 MTs, employing 3994 team members, operating on haodf.com , a Chinese OHC, to examine effects of both leader and team characteristics on TSD. Results Our findings suggest that a MT’s characteristics have a significant impact on TSD. Firstly, the decisional capital of both leaders and teams were positively related with TSD, while only the status capital of leaders saw a positive impact. Secondly, team heterogeneity influenced TSD in two ways: (1) provided a direct negative impact and (2) positively moderated the relationship between professional capital and TSD. Conclusion This paper comprehensively studies the impact of TSD from the perspectives of professional capital and team heterogeneity, expanding current theoretical understanding of team heterogeneity and social capital in OHCs. Further, it provides practical suggestions for platform development and team leaders managing MTs in online environments.