The 3Rs framework — Replace, Reduce, Refine — guides the ethical use of animals in research, with significant advances in alternatives reducing animal use while maintaining scientific validity.
The 3Rs framework has driven sustained reduction in animal use across biomedical research — annual figures have decreased substantially in many jurisdictions over decades. The welfare case for alternatives development is straightforward: every valid alternative that replaces an animal test or allows a study to be conducted on fewer animals reduces suffering. Refinement delivers immediate welfare gains without requiring replacement, making it the most accessible component of the 3Rs for most researchers. The scientific case for alternatives is increasingly compelling — human organ-on-a-chip models may better predict human drug responses than traditional animal models, making alternatives both welfare-positive and scientifically superior in some applications.