Animal testing and research: the facts | Replacing Animal Research

Headline Figures: 2025 at a Glance

2.54 million scientific procedures used animals in 2025. This is a 3.8% drop from 2024 and the lowest number recorded since ASPA came into effect in 1987.
100,613 fewer procedures were carried out compared to the previous year. Every single decrease is a step in the right direction.
A downward trend in licensing indicates a small drop in the number of licensed establishments and active project licenses, meaning fewer research institutions are applying to use animals.
95% of all procedures used mice, rats, birds, or fish.
52% of all procedures were experimental procedures
54% of experimental procedures were for basic research, which involves studying the human body to understand its functions, identify potential problems, and develop solutions. The top three research areas were the nervous system, the immune stystem, and cancer.
19% of all experimental procedures were for regulatory research, like the development of medicines or the safety testing of chemicals.
48% of all procedures were for the creation and breeding of genetically altered animals.
1.3% of all procedures used specially protected species (cats, dogs, horses, and non-human primates).
These statistics cover England, Wales, and Scotland. Northern Ireland is reported separately.
The UK reports on the ‘number of regulated procedures’ using ‘protected’ animals, and the number of animals used for the first time. But not the total number of animals.

Worldwide, the best estimates are that between 100 and 150 million animals are used yearly in scientific research.

Specially Protected Species: A Troubling Rise

While overall numbers fell, looking beneath the headline data reveals a more complex and disheartening reality for specially protected animals. Some of the numbers relating to specially protected animals, such as dogs, cats, and non-human primates, actually increased:

The number of non-human primates being used in scientific procedures for the first time has increased from 1,478 in 2024 to 1,845 in 2025.
The number of dogs being used in scientific procedures for the first time has increased from 1,651 in 2024 to 1,706 in 2025.
And, the number of experimental procedures using cats has increased by 11% from 2024.

These increases are a sobering reminder of how much work remains to be done, and why progress can feel painfully slow.

What don't the stats tell us?

Statistics on animal use in science are compiled and published by the UK Home Office annually from data submitted by establishments holding a licence to conduct animal research.

However, because official statistics only count the number of ‘regulated procedures’ on ‘protected’ animals and animals used for the first time, they never capture the full extent of animal use.

Not all animals bred for research will undergo a ‘regulated procedure’. This creates a significant gap in our understanding of what happens to these animals or how many animals are actually involved in science.

Not every animal is protected under animal research legislation either. Despite their sentience being recognised, some invertebrates like lobsters and crabs, currently have no real legal protection.

It also means they aren’t counted in the stats.

Not including these animals is, at best, compromising the use of the annual statistics to accurately reflect the scale of animal use for science, and at worst, is actively misleading the public on the number of animals involved in research.

Your questions answered:

What happens to animals after they’re used in research?

It depends. Some animals will die because of the experiment, most will be killed afterwards, and some will be used in more experiments. In rare cases, some animals are ‘rehomed’ after being used in research, but this must be planned in advance, and has no legal requirement.

The definition of ‘rehoming’ in the legislation includes being transferred to another research establishment abroad, a slaughterhouse, a farm, or a zoo, as well as being rehomed as a pet. This definition is very misleading.

How many animals are used in research worldwide?

We don’t know. No one does. The UK reports on the ‘number of regulated procedures’ using ‘protected’ animals, and the number of animals used for the first time. But not the total number of animals.

Worldwide, it’s estimated 45% of countries with evidence of ‘significant’ animal use in science have no official statistics.

Our best estimates are between 100 and 150 million animals.

Why are animals still used if alternatives exist?

Animal research is still the ‘norm’. Researchers, reviewers, and educators have been trained to believe animal research is essential and don’t feel confident finding, and using, new non-animal methods which may be a completely new skill set to them. This is part of what we call ‘animal methods bias’, and it’s something we’re supporting the scientific community to overcome.

Non-animal research doesn’t receive the same level of support or funding. That’s why we’re here.

Where replacement methods already exist, we empower researchers and policymakers to become confident with using them and helping them move away from animal methods. We’re also working hard to ensure the legal requirement for researchers to explore alternatives before requesting a licence for animal research is being done and reported properly.

Where replacements don’t exist, we have several funding opportunities to support their development and promotion.

Learn more about alternatives to animal research.

Animal research vs. animal testing: Is there a difference?

Yes, there is! And it’s quite a significant difference.

So, what is animal testing? Animal testing tends to refer to regulatory testing and is often a legal requirement. This involves things like testing household products for their safety, or, historically, cosmetics testing. 21% of experimental procedures in Great Britain were for regulatory testing in 2023.

Animal research is a much broader term and is the biggest user of animals. Animal research often refers to ‘basic research’. Basic research is how researchers build their knowledge base on human health issues like cancer. In basic research, there is no legal obligation to use animals, so researchers have much more scope to explore non-animal methods

Learn more about animal testing vs animal research.

What is a regulated procedure?

A regulated procedure is defined as any action causing more discomfort than an injection on an animal protected under the Animal (Scientific Procedures) Act 1986.

This is quite a broad definition and certain research can be hard to compare to a needle injection.

How we're making a difference

The majority of animal research happens at universities and research institutes, so that’s where we focus a lot of our energy.

We empower researchers through our funding and educational activities. This gives researchers practical experience with non-animal research, support developing new methods, and more confidence challenging the status quo where animal research remains the ‘gold’ standard.

But that’s not all. To ensure no animal suffers for science, we need systemic change at every level, including the Government. Our Policy work sees us collaborate with policymakers to improve legislation to protect animal welfare and ensure non-animal methods are the priority.

Animal testing and research: The facts and figures

Animal testing and research statistics in Great Britain

2.54 million

95%

1%