The 3Rs framework — Replacement, Reduction, and Refinement — has guided laboratory animal welfare for 60 years. Understanding what progress has been made and what barriers remain reveals where investment and advocacy can accelerate change.
Laboratory animal welfare has improved substantially under the 3Rs framework, with refinements to anaesthesia, analgesia, and housing standards reducing the severity of many procedures. Replacement technologies — particularly organ-on-a-chip, organoids, and advanced computer modelling — are increasingly viable alternatives for specific research questions. However, replacement is not yet possible for many complex biological systems, and reduction efforts are constrained by statistical power requirements. The welfare challenge is that millions of animals still experience pain, distress, and death each year in research that could in principle be conducted in other ways if investment in alternatives were higher. The most impactful welfare interventions are increased funding for NC3Rs, regulatory incentives for alternative methods, and validation frameworks that make alternative assays acceptable to regulators.