This article demonstrates that ‘bodies at risk' in sexual health are socially constructed. It does so via a heuristic comparison between two molecular technologies that are central to the promotion of sexual health: the combined oral contraceptive pill (COCP) and pre-exposure prophylaxis (PrEP). Drawing on ethnographic research conducted in two sexual health institutions in the western part of Switzerland, the article presents two main findings. First, it argues that bodies are constructed as being at low or high risk by sexual health professionals (based on health and lifestyle criteria). Second, it shows that access to either the COCP or PrEP is largely based on this former classification. The article also demonstrates that there are ambivalent situations in which sexual health professionals seek compromises between different risks, and pragmatically adapt their medical protocols.