Regulatory reform in the cosmetic and personal care chemistry sector in Kenya has repeatedly stalled despite formal policy commitments and institutional mandates. Drawing on the theoretical resources of historical institutionalism and principal-agent analysis, the article identifies three boundary conditions that jointly determine reform trajectories: the fragmentation of regulatory authority across multiple agencies, the weak coupling between policy formulation and enforcement capacity, and the absence of feedback loops linking consumer harm to political accountability. The analysis demonstrates that implementation failure is not primarily a technical deficit but a structural feature of how regulatory authority is distributed and exercised. The framework is illustrated through the Kenyan case but is designed to be portable to other African jurisdictions with similar regulatory architectures.