The European Union’s REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) Regulation aims to ensure high levels of human health and environmental protection, while also promoting alternatives to animal testing. REACH permits animal testing as a last resort only and imposes the 3Rs principle (Replacement, Reduction, and Refinement of animal testing). Nevertheless, the current regulatory practices still heavily rely on animal-based methods. This study underscores the scientific limitations of animal models and highlights the ethical and methodological burdens associated with their use. It synthesises the challenges and opportunities associated with integrating New Approach Methodologies (NAMs) into regulatory toxicity testing under REACH, as highlighted by various scientific experts. Key challenges identified include contradictory and inadequate legislative frameworks, slow and restrictive validation processes, low acceptance of NAMs by regulatory authorities, and legislative amendments expected to increase animal testing. To create a more flexible regulatory environment and advance the adoption of NAMs, there is a need for legislative reforms and increased collaboration between academia, industry and regulatory bodies. In this context, it is also necessary that more legal scholars begin to show interest in this field to help tackle the multidisciplinary challenges to non-animal testing for regulatory purposes. This article provides an introduction to the field of regulatory toxicology with a focus on the REACH framework from a legal perspective.