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What are the 3Rs?

The 3Rs aim to replace animal studies with non-animal methods and approaches (Replacement), reduce the use of animals (Reduction) or refine their welfare and conditions (Refinement). Replacement, reduction, and refinement must be considered as a whole in the planning of each study involving animals. Following the 3Rs is a firm legal requirement. They are constitutive principles of the Finnish national legislation and EU Directive on the protection of animals used for scientific or educational purposes.

The 3Rs were defined in 1959 by the English researchers William M.S. Russell and Rex L. Burch in “The Principles of Humane Experimental Technique” (Alternatives to laboratory animals: ATLA 43(5):P59-P60, DOI:10.1177/026119291504300518).

The 3Rs and their impact on research




Whenever possible, laboratory animals must be replaced entirely or partly by a scientifically reliable method, approach or testing strategy that excludes the use of live animals.


Replacement methods include, for example: human tissue and cell culture (in vitro), computer models (in silico), methods and systems based on biochemical approaches such as synthetic (macro)molecules (in chemico), omics technologies, and methods based on existing data, such as quantitative structure-activity relationship (QSAR) modelling (in silico) and read-across techniques.


  • Living animals can be replaced.

  • Promotes the development and implementation of tissue, organ, and disease models to replace animal experiments either entirely or partly.

  • Adds molecule-level data on signalling routes, key events and mechanisms, among other things.

  • Fits for the Next Generation Risk Assessment strategy. 




Researchers must use any approach that will result in use of fewer animals without compromising the experiment’s objectives and scientific reliability Furthermore, the information obtained from an individual animal must be maximised.


  • Study design.
  • Statistical methods.
  • Sharing tissues and organs with other researchers when using the same study protocol. 
  • Reusing animals whenever possible while maintaining scientific objectivity and the welfare of the animals.
  • Collecting all possible information during the experiment: clinical signs, animal weight, food and water consumption, haematology, clinical chemistry, pathology, histology, omics, and biomarkers.


  • Promotes the careful planning and analysis of animal studies, and the evaluation of a study´s significance as a source of new information.
  • Allows existing material to be used for new research questions.
  • Reduces the number of laboratory animals.



The methods of animal breeding, maintenance and care, as well as procedures on animals, must be improved to avoid distress, pain, suffering or lasting harm, or to minimise these to the greatest extent possible. 

The obligation to refinement also includes maintenance and care of animals to give them a good life from birth to death.


  • Keeping animals in conditions and facilities that allow behaviour typical for their species.
  • Training staff to be competent in the care and handling of animals.
  • Acclimatizing animals to staff, handling, and study procedures.
  • Using appropriate pain relief and anaesthesia.
  • Improving research techniques.
  • Using non-invasive methods.
  • Selecting the most appropriate species for each study.


  • Promotes animal welfare and reduces suffering.
  • Promotes the development of new methods that improve welfare.
  • Reduces the number of laboratory animals.
  • Increases the reliability of research results.


The Finnish Act on the Protection of Animals Used for Scientific or Educational Purposes (497/2013) and the decree (564/2013) entered into force in 2013. Both are based on Directive 2010/63/EU. The above national regulations also include the provisions regarding the Council on the Protection of Animals Used for Scientific or Educational Purposes (TOKES) (decree 565/2013) that is tasked with promoting the 3Rs.

TOKES has determined that animal welfare is based on the animal’s own experience of its mental and physical condition. Possibilities for adapting to environmental conditions and events, and possibilities to control environment, affect the welfare of an animal.  The welfare is also affected by animal  genome and any alterations thereof, as well as their health, environment, care and study procedures. The life of a laboratory animal should be as good as possible from birth to death. By law, animals used for scientific or educational purposes must be subjected to the minimum of any possible distress, pain, suffering and lasting harm.