Reprioritizing the 3 R’s

Sixty years ago, William Russell and Rex Burch introduced the concept of the “3 R’s”— the replacement, reduction and refinement of animal use— in an effort to advance animal welfare standards and reduce animal use in science.

In many ways, the world of biomedical sciences is very different now compared to when the 3 R’s were first established, considering the advancements that have been made in the development of human-relevant alternatives. Non-animal models that were not even imaginable 60 years ago have been developed, including organs-on-chips, disease-in-dish models made from human induced pluripotent stem cells, and sophisticated computational models. These models continue to be developed, refined and improved and offer a lot of potential to replace animal use.

NAVS is proud to play an important role in funding, through the International Foundation for Ethical Research, these and other non-animal alternatives. These models represent the future of scientific advancement, which is why we were excited to read a recent paper published in ALTEX that reexamined the 3 R’s and offered suggestions that scientists should consider adopting as we move forward into the future.

The authors suggested a three-pronged approach to bring us closer to the day where scientists do not rely so heavily on animal models:

1) Focus on the use of alternatives as replacements to animal models

When Russell and Burch developed the 3 R’s concept, they prioritized replacement as the ultimate goal, followed by reduction and then refinement. However, in the intervening years, researchers have tended to regard refinement as a top priority, followed by reduction, and then replacement. Because of inherent species differences between humans and animals and the new human-relevant models that are available and being developed, more effort must be focused on replacing animal use with non-animal approaches.

2) Prioritize applying the use of alternatives to biomedical research

While there has been widespread talk of the need to replace animal use in toxicology and regulatory testing when possible, replacing animal use in basic and applied research would have a larger impact, as most animals are used for this type of research.

3) Focus on making alternatives as human-relevant as possible

We know that human-relevant models do a better job of accurately reflecting human biology, and that they give us the best chance of improving human health and well-being. If researchers make using human-relevant, animal-free methods a priority, this would avoid relying on data from animal models that have limited translational value.

The authors note that by encouraging the use of reliable, human-relevant, non-animal alternatives as replacements to animal models in broader areas of research, we can help “move forward towards a new era in the history of humane experimental technique.” NAVS could not agree more.

Help NAVS continue to fund the development of these human-relevant in vitro and in silico models that can replace animal use, so that the 3 R’s can be implemented in the manner in which they were intended.



Herrmann, K., et al, “Beyond the 3Rs: Expanding the use of human-relevant replacement methods in biomedical research,” ALTEX, July 2019.

This entry was posted in News and tagged on October 21, 2019.
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