The 3Rs framework — Replace, Reduce, Refine — guides efforts to improve laboratory animal welfare while maintaining scientific progress. Implementation varies widely across countries and institutions.
The 3Rs provide the dominant ethical framework for laboratory animal welfare globally and have driven genuine improvements over six decades. Refinement has been the most consistently implemented R: anaesthesia and analgesia are now standard, and enriched housing for mice and rats is increasingly mandated. Reduction has been driven partly by statistical awareness and partly by funding pressures. Replacement remains the most aspirational R, with organ-on-chip technology, advanced cell culture systems and computational modelling offering growing possibilities. The challenge is that implementation is uneven — high-income countries with strong regulatory frameworks achieve far higher welfare standards than those in lower-income research settings. International harmonisation of welfare standards remains an important goal.