In this paper, we conceptually situate the role of IT designers in regulation through the new concept of User-Centric Regulation (UCR). New regulatory problems arise as users increasingly interact with data-driven technologies embedded in their daily lives, routines, and relationships. Rights and responsibilities from privacy and data protection, accessibility, information security, tort and consumer protection laws can all come to the fore. However, the differential pace of change between legal instruments and technological advance creates a disconnect between the mechanisms and targets of regulation. To bridge this gap, there is a turn to IT designers, as a new type of regulator, who can address regulatory problems earlier in the lifecycle of a product or service. However, the nature of their new role remains unsettled and in this paper, we explore what type of regulators they might become, through UCR. Three key elements are needed to support the emergence of UCR, firstly mutual learning around how each community engages with regulatory problems; secondly, sourcing routes to establish the legitimacy of IT designers in regulation; and thirdly, finding mechanisms to support IT designers acting on their ethical and legal responsibilities. We explore these issues by consolidating work from the fields of human computer interaction (HCI) and information technology (IT) law, as specific domains of IT design and regulation. We lay out theoretical tools and conceptual frameworks available to each community, exploring barriers and commonalities between them, to propose a route forward: UCR.