This article develops the concept of temporal total institutions to describe how and why individuals voluntarily submit to highly-controlled and often dehumanizing environments. We focus empirically on Phase I clinical trials, which offer compensation to healthy people in exchange for testing investigational pharmaceuticals. Analyzing the experiences of 67 U.S. healthy volunteers, we illustrate how comparisons between Phase I trials and prison are salient to participants as they reflect on their confinement in research facilities and their interactions with other participants and research staff. We argue that conditions of contemporary economic insecurity and/or poverty facilitate the existence of coercive temporal total institutions by undermining voluntariness. Phase I clinics take advantage of the steady supply of individuals who will submit to the organization's demands out of hope that the income gained will be transformative for their lives.