Marin and Miller (2013) proposed interpersonal sensitivity (IS), characterized by ongoing concerns about social threats, as a new model to integrate research on interpersonal traits and health. They concluded that IS is associated with infectious and cardiovascular disease but not cancer or all-cause mortality and discussed a clear agenda for future research. However, the evidence on IS and health is mixed, and there still is much to be learned about the pathways that underpin these associations and moderators that reveal at what age and in what subgroups such associations hold. Marin and Miller noted that a toxic core of IS could be social inhibition, a related but distinct trait that refers to inhibited behavior during social interaction. On the basis of their proposition, I suggest an alternative model that points to social inhibition as an underlying trait that paves the way to IS. Social inhibition is a major determinant of chronic social stress in children and nonhuman primates. Yet, it remains uncertain whether social inhibition and its interaction with negative affectivity in Type D personality, is also related to health outcomes in adults. Many other challenges remain, but this important work of Marin and Miller highlights the need for more research on IS, social inhibition, and health.