In recent years, contemporary society – particularly in the West – has witnessed a growth in the production, promotion and consumption of pharmaceutical products, particularly for disease treatment. The process of producing these medicinal products involves testing for safety and efficacy on, among others, healthy human subjects. Taking a phenomenological approach, this thesis examines how risks, rewards and regulation associated with first-in-human clinical trials (FIHCTs) are viewed and experienced by regulatory and corporate professionals, and by healthy volunteers. Using conceptual and empirical forms of inquiry, the study shows how current understandings of human involvement in clinical trials heavily influenced by bioethical conceptions of healthy volunteers as rational, altruist and willing participants, limits our appreciation of the context in which such acts take place. This is because the decision to take part in trials is shaped by the situation in which people find themselves. Appeals to rationality, altruism and voluntarism do not explain all the elements that go into that decision. Therefore, new insights into the lives of healthy volunteers challenge bioethical conceptions and generate new frameworks for policy and practice of FIHCTs. Having identified a gap in medical sociology research on healthy volunteering in FIHCTs in the UK, this qualitative research project brings the findings of extensive desk and field research into analytical discussion. Specifically the research examines existing regulatory discourse and practices around the implementation and conduct of clinical trials and experiences of healthy volunteers in clinical trials in the UK. It investigates how the different actors view and experience the risks that emanate from medical technological innovations, and how their views shape human involvement in drug testing. Data were gathered from documentary analysis, interviews with 4 corporate professionals, 8 regulatory officials and 35 healthy volunteers, and a survey of 187 healthy volunteers. This research breaks ground for further social scientific research into healthy volunteering in FIHCTs in the UK. Specifically it adds to calls for more nuanced discussions of human involvement in clinical trials and the unpacking of concepts such as “volunteer”, “compensation” and “informed consent” in clinical trial contexts. Schutz's (1970) “system of relevance” is used as a tool for studying the interaction of risk, rewards and motivation for both the “individual” and the “institution”. The findings show that the existing regulatory system is fragmented, and healthy volunteers are often pushed to the margins of the regulatory system. In addition, regarding participants in clinical trials as “willing volunteers” serves to obscure the ways in which inequality is perpetuated and experienced by some participants in these early studies. The thesis concludes by suggesting that Schutz's system of relevances offers a valuable insight into the study of healthy volunteering.