Obesity drugs were subsidised by the Swedish state up until April 2001, when enor-mous increases in drug costs forced authorities to make priority lists. So called "life style drugs" such as drugs against obesity and impotence were taken off the subsidy list. Actors such as obesity researchers and public officials have since then debated over whether obesity should be seen as a health risk or a disease. This debate also resonates at a local obesity clinic/research department level where a dominant part of staff are involved in clinical trials on potential future obesity drugs. Framing overweight as a risk or disease respectively, reflects the sometimes differing inte-rests of obesity research, public health care and the pharmaceutical industry. In this paper, these obesity drug. In focus is the ways in which heterogeneous actors per-form boundary-work around two flexible objects central in clinical trial practice: the protocol and the participants. The paper describes the flexibility of the group of voluntary participants and the clinical protocol, where they are enrolled as tools for research, treatment or pharmaceutical production, in complex ways and depending on the situation.