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The replacement, refinement and reduction (3Rs) in research using animals


The principles of the 3Rs, replacement, refinement and reduction, were originally developed by Professor William Russell and Rex Burch, and are now widely accepted internationally as criteria for humane animal use in research and testing.


All animal research funded by BBSRC must integrate the principles of 3Rs. The aim of this priority is to advance further improvements through the development, integration and promotion of 3Rs approaches (Replacement, Reduction and Refinement). Researchers whose main focus of research may not be the 3Rs are also strongly encouraged to look for new opportunities within their proposed programmes of research to improve animal welfare and/or to drive forward new advances in the application of 3Rs principles.

Scientific scope

The 3Rs are defined as:

  • Replacement: Methods that avoid or replace the use of animals defined as 'protected' under the Animals (Scientific Procedures) Act 1986 in an area where they would otherwise have been used. Examples include:
    • Absolute replacements – techniques which do not involve animals at any point, such as computer modelling, in vitro methodologies (e.g. tissue engineering), use of human volunteers
    • Relative replacements, which replace the use of 'protected' animals with other species e.g. invertebrates, larval forms of amphibians and fish until the stage where they become capable of independent feeding
  • Refinement: Improvements to scientific procedures and husbandry that minimise actual or potential pain, suffering, distress or lasting harm and/or improve animal welfare in situations where the use of animals is unavoidable. Examples could include reducing stress by developing new approaches such as training animals, use of non-invasive techniques or enrichments that improve living conditions
  • Reduction: Methods that minimise animal use and enable researchers to obtain comparable levels of information from fewer animals, or to obtain more information from the same number of animals, thereby reducing future use of animals. Examples could include: Improved experimental design and statistical analysis; data and resource sharing; and use of techniques such as imaging

These principles must be embedded in all the research within our remit involving (or potentially involving) animal use. We encourage grant applicants, including those whose research does not involve animals but could contribute to greater reduction and replacement, to consider further opportunities to advance the 3Rs. Applications that do not exclusively address improvements in the 3Rs will fit this priority if they aim to generate new improvements in the 3Rs as part of a larger or related study.

Outputs and impacts

Outputs of 3Rs research are expected to have wide policy and societal impacts including addressing both the Government's priorities in reduction and replacement, and public concerns about the use of animals in research. More specifically there is increasing evidence that aspects of refinement not only benefit animals but can improve the quality of research results. Outputs could also include development of novel replacement, or non-invasive technological refinements that may lead to reductions in the financial costs of research.


In proposing activities during the project to explore possible translational opportunities applicants should demonstrate awareness of policy and societal implications and are advised to consult the National Centre for 3Rs (NC3Rs) website (see external links) which provides a valuable source of information that should be used to ensure maximum value is derived from the research.

BBSRC is one of the funders of the NC3Rs, which provides a UK focus for the promotion, development and implementation of the 3Rs in animal research and testing. The NC3Rs has a 3Rs Research Funding Scheme for hypothesis driven and applied research that will advance knowledge and application of the 3Rs.

Ethical and other issues

Applicants are expected to adhere to the general principles and best practice outlined in the Responsibility in the use of animals in bioscience research guidance (see downloads), and the ARRIVE (Animal Research: Reporting In Vivo Experiments) guidelines.

Applicants should also be aware of the European legislation on the protection of animals used for scientific purposes (Directive 2010/63/EU) and the resulting UK Animals (Scientific procedures) Act 1986 Amendment Regulations 2012

Data sharing

Data and resource sharing are encouraged as part of addressing the 3Rs. Where relevant, applicants should address the shared funders' position statement on sharing and archiving of genetically altered mice (see downloads).