Precautionary measures (PMs) are granted by regional and international human rights bodies to protect persons who are in a situation of extreme danger. In Central America, these measures are overwhelmingly granted to at-risk detainees who face risks to their right to life, integrity and/or health. When a PM is granted, the State is required to provide detainees with immediate access to food, drinking water, fresh air, medical care or natural light. PMs have the potential to save lives, requiring immediate State action for the protection of vulnerable populations. Despite the fact that PMs have been issued on thousands of occasions, any academic studies that exist on the matter focus on a doctrinal analysis of compliance, failing to pay heed to the practical effectiveness of these measures on the ground. In light of these shortcomings, the aim of my proposed research is to move beyond traditional legal research and to take a broad socio-legal stance, analysing the effectiveness of PMs de facto, with the ultimate goal of maximising their practical protective effect. In light of the findings, this PhD project will develop a critical normative legal impact framework for PMs in order to produce a framework with practical societal effectiveness, ensuring that international human rights law is not simply aspirational but is practical and effective. Overall, this project seeks to improve the robustness of international law to produce a meaningful impact.