This article revisits the conceptualisation of pharmaceutical regulation. While States and multilateral organisations play a central part in devising rules, regulation as a social practice extends beyond their role. Domestic and international interests, geopolitics and spatial configurations, commercial and health considerations, governmental policies and individual behaviours and legal and illegal transactions all contribute to regulating the pharmaceutical milieu. This consideration expands the epistemological range of pharmaceutical regulation, which then appears as the assemblage of heterogeneous laws, rules and codes of conducts. The way in which these layers are connected forms what regulation actually is in practice. Regulation multiple thus appears as the product of tensions between harmonisation efforts and persistent diversity, as well as the result of interactions and overlaps between official regulation and unofficial regulatory practices. This article explores these tensions in the Southeast Asian pharmaceutical market along three themes: circuits and logistic regimes; control and attention to quality; bridges and harmonisations.