Mobile Health (mHealth) technologies are increasingly becoming an essential part of healthy lifestyles, disease prevention and disease management. The field is developing at a rapid pace, with emerging mHealth technologies being met with enthusiasm and promoted as tools to revolutionize healthcare. We believe that a wide implementation of mHealth technologies can have a transformative impact on health care provision and that it can significantly shape health care systems and public health outcomes. In this paper, we interrogate the major challenges accompanying such developments. Considering the hopes associated with mHealth technologies, we find it important to open a discussion about their challenging aspects, including the emphasis on self-monitoring, -management and -responsibility for health (implicit in and reinforced by mHealth) algorithmic biases, technological risks, increasing influence of the private IT-sector and new roles for health care professionals. The overall aim of our analysis is to support responsible, socially sustainable and user-centric innovation in mHealth.