Co-producing research is complex and messy. This paper draws on Tina Cook's argument for the systematic inclusion of 'mess' in research accounts as a conceptual framework through which to articulate areas of ethical mess from within a co-produced research project. Through narrating the 'messy' ethical complications the paper illustrates a number of specific ethical risks when co-producing research; particularly when working with young people. The paper provides valuable insight into ethical tensions that can emerge when using a co-produced methodology and will be informative for future researchers negotiating their own co-produced research projects. The paper argues for the systematic inclusion of mess in the accounting of participatory research.