The article intervenes in discussions on lay knowledge production about health in the Internet era, through the case of a group of women claiming that their use of copper intrauterine devices has led to systemic side effects. Based on online group interviews and written essays, we examine how women embracing these knowledge claims navigate various sources of information, focusing on the role of scientificity in these epistemic negotiations. The women were found to be involved in an active, scientifically oriented process of knowledge formation, which we refer to as a collective labour of scientific patchworking. Meanwhile, due to a perceived lack of scientifically based expertise on their condition, the women reported having little choice but turn to resources with weaker scientific foothold. We argue that the tendency to portray these women’s claims as unscientific simplifies the nature of lay knowledge production, potentially deepening divides between medical authorities and the public.