Use of animals

We take our moral and societal responsibility to animals seriously by providing high standards for the care, welfare and treatment of all animals in our charge.

Lab worker tunnel handling a white mouse

Our company-wide policy

We use animals for research studies when their physiology and disease process is similar to that in humans. When using animals, we follow scientific principles to ensure that we prevent or minimise pain and distress before, during, and after experimental procedures.     

Our company-wide policy covers the standards of care and the ethical treatment of animals in research, development and testing of all GSK medicines and vaccines. All GSK animal research must comply with this policy.

We actively observe our policy by:   

  • Investing in the development and validation of replacement technologies, including complex in vitro models and in silico models.  
  • Applying appropriate statistics in study designs to answer the scientific question using as few animals as possible.  
  • Engaging experts and specialists in humane care to minimise any pain or distress to animals, and actively pursue initiatives to improve animal welfare based on current animal welfare science.  
  • Employing trained specialty staff, including qualified veterinarians, available at all times for advice and help with clinical care.  

Non-human primates

Less than 0.2% of the animals we use in our studies are non-human primates. However, in some cases, non-human primates are the only animals similar enough to humans to provide the critical information about a disease and its reaction to treatment.  For example, a new medicine may be based on a molecule produced only in primates, including humans, and would be destroyed by the immune system of other species.   

  • We only use non-human primates in research projects if no other species is appropriate for the purposes of the programme. These non-human primates have been specifically bred for use in research.  
  • We do not fund any studies using great apes - a sub-group of non-human primates which includes gorillas, chimpanzees, orangutans, and bonobos.  
  • We recognise that studies involving chimpanzees have played a vital role in the understanding of many diseases that affect humans: specifically infectious diseases such as hepatitis C and HIV/AIDS. However, we also recognise that due to the advancement of alternative animal models and other biomedical research techniques, there is no longer a need for these animals in any of our work. 

How our work is monitored 

Highly trained staff look after our animals throughout their lives. A veterinarian or veterinary nurse is onsite or on call 24 hours a day, seven days a week. Regulatory bodies also visit our facilities regularly and often unannounced.   

All of our facilities and programmes comply with the national laws, guidelines and codes of conduct for that country. In situations where we have recently acquired a company, or carry out work with a third party organisation to conduct animal-based research on our behalf, we will work closely with that group to align them with our animal welfare standards.  

In addition, all our hub sites are accredited by AAALAC-I, a voluntary accreditation body that harmonises standards in animal welfare across the globe. This independent group reviews and assesses our animal care programme against published standards and industry practices.

Our work with other organisations

We share our practices with other scientists and regulatory authorities and publish the results of our research in scientific journals. We also work with organisations that aim to reduce the need for and refine the use of animal testing, including, but not limited to:  

  • European Centre for the Validation of Alternative Methods (ECVAM)  
  • European Partnership for Alternative Approaches to Animal Testing (EPAA)  
  • European Animal Research Association (EARA)  
  • International Consortium for Innovation & Quality in Pharmaceutical Development  
  • Institute for Laboratory Animal Research (ILAR), part of the US National Academy of   Science, Engineering and Medicine  
  • National Centre (UK) for the Replacement, Refinement & Reduction of Animals in Research (NC3Rs)  
  • The North American 3Rs Collaborative  
  • Scientist Center for Animal Welfare (SCAW)  
We are deeply thoughtful about the use of animal experiments in drug discovery research, minimising their use to circumstances where they are required by regulation, or have clear scientific merit in defining the potential dose, safety or efficacy of new medicines for patients. In parallel, we are investing in novel experimental systems based on human cells and tissues that hold promise of further reducing the need for animal experimentation.

John Lepore, Senior Vice President and Head of Research.

The 3Rs at GSK

Our 3Rs[1] strategy of replacement, reduction and refinement is a science-led, ethical framework that we use to guide us in our work with animals. Where animal research is conducted or commissioned, we are advancing the 3Rs (Reduction, Refinement, Replacement) and seeking ways to minimise animal use and reduce the impact on the animals.

R&D scientist setting up Prodigy machine whilst working in cell and gene therapy.



Accelerating the development and use of models and tools, based on the latest science and technologies, to address important scientific questions without the use of animals.

R&D scientist developing and discussing chemistry formulas in smart laboratory.



Appropriately designed and analysed animal experiments that are robust and reproducible, and truly add to the knowledge base.

Mice in bedding



Advancing animal welfare by exploiting the latest in vivo technologies, and by improving understanding of the impact of welfare on scientific outcomes.

Across GSK, where animal research is conducted or commissioned, we are advancing the 3Rs and seeking ways to minimise animal use and reduce the impact on the animals. Wherever possible, we pursue new methods and technologies that do not require animals such as in vitro models and in silico prediction. 

When we do use animals, the best experimental design is achieved through application of statistical principles to ensure the minimum numbers of animals are used to answer scientific questions. Peer review occurs from additional scientists, biostatisticians, animal welfare specialists and veterinarians. 

We are continuously improving animal welfare through shared learnings, housing and husbandry refinements and technologies. All our proposed animal research is reviewed by ethical panels. These panels consider animal welfare and the 3Rs prior to the approval of our studies.


[1]The 3Rs principles were developed in 1959 with the standard definitions recently expanded by the NC3Rs.

We are modernising the 3Rs; moving towards a strategy anchored in the contemporary definitions of Replacement, Reduction and Refinement. For GSK this means enhanced focus on scientific rigour and translational relevance along with the established cornerstone of animal welfare.

Margaret Landi, Chief Veterinary Officer, GSK

Replica of organ on a chip
Organ on a chip - credit: Emulate, Inc

Non-animal methods include computer simulation (in silico) work to identify and select promising drug candidates. Investments in new technologies and models such as organ-on-chip, organoids and 3D bioprinting allow use of innovative technologies at early stages of medicines discovery and to explore human safety signals. Understanding the effects and side effects of molecules on human cells and tissues in these technologies may facilitate replacing animals in the longer term. 

This is a fast-developing field, and we collaborate on multiple projects spanning from design to implementation phase. GSK has active representation in organisations supporting non-animal technologies such as EUROoCS, NA3RsC’s Microphysiological Systems Initiative, NC3Rs and others.

The majority of GSK vaccines no longer require animal testing for release and stability programs. In vitro assays such as relative potency and monocyte activation tests enable faster evaluation of safety and efficacy. These new, non-animal methods are rapid and highly sensitive, and decrease the time it takes to get lifesaving vaccines to patients. 

We are progressing towards our target of reducing animals used in vaccine quality control testing by 75% in the timeframe from 2015 to 2025. 

Industry-wide efforts are resulting in further non-animal technologies (NAT) to test the safety and efficacy of new and existing vaccines. Through external collaboration, GSK develops and validates methods to ensure early adoption of novel technologies and the substitution of animal tests. Collaborators include the Innovative Medicine Initiative, NIIMBL, EFPIA, EPAA and others.

  • Pre-clinical bio-imaging allows large amounts of data to be obtained from individual animals. For example, new technologies allow visualisation of drug distribution or changes in tumour burden, and each animal can be assessed over time – further reducing the number of animals needed in studies.
  • Robust design of animal experiments is critical to ensure high quality and reliable data. To reduce bias, we take important statistical principles like randomisation and blinding from clinical trials in patients and apply them to our animal studies. We also include the fewest animals required to answer the scientific questions appropriately.
  • Automated blood sampling has been refined in partnership with cage manufacturers - resulting in rats remaining in their home cage during sampling.
  • Techniques for handling of mice, such as tunnels and cupping, are shared across handlers in all facilities to enhance the lifetime experience of animals in our care.

FAQs about animal studies

Animal research is still necessary to discover and develop new treatments for people. This is because animals have similar, though not exact, physiological and biological functions to humans. They also have much shorter lifespans, meaning we can study the effect a new drug or vaccine in animals during their full lifetime and in multigenerational studies when required.

Animals are susceptible to many diseases that affect humans, including cancer, cardiovascular and immunological diseases. Animal research therefore provides our scientists with an opportunity to simulate the effects of disease and medicines on the human body while determining the safety and efficacy of a new drug or vaccine. Regulatory authorities require safety and efficacy testing in animals before entering clinical trials in people.

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We use alternatives to animals wherever we can. We employ non-animal models whenever possible and apply the 3Rs to ‘replace’, ‘reduce’ and ‘refine’ animal research. Unfortunately, there is currently not always an alternative that allows us to see the effects of a new medicine on a living body. Therefore, when there are no alternatives available or when required by regulatory authorities, we use animals for research and testing.  

Find out more about our efforts to replace, reduce and refine.

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The actual number of animals we use always depends on the number and type of studies we are carrying out. This changes year to year.  In 2023, we required 148,766 animal uses.

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All animals needed for the discovery and development of new treatments are bred specifically for research by approved vendors that we regularly audit. We never use pets or strays. Rodents and rabbits make up 99.1% of the animals we use for research. The remaining animals include pigs, dogs, chickens, turkeys, sheep, goats, cattle, and non-human primates. 

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Since many of our studies are minimally invasive (e.g., taking blood or urine samples), with approval from our veterinary team and the regulatory authorities, and if we are confident there are no lasting effects from any administered compound, we will use the animals again for research on a similar study. 

For other studies, we humanely kill the animal at the end of the study to gain information about the effects of a potential new treatment on an animal’s tissues or organs.

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A comprehensive system of government oversight is in place to regulate the use of animals for scientific purposes:   

  • The Home Office regulates animal research in the UK and in Europe the Directive EU 2010/63 outlines regulations.  
  • The Animal Welfare Act covers animal research in the US.   
  • All our internal sites and many external locations are also accredited by AAALAC International, a global voluntary accreditation and assessment process that reviews animal care and institutional programs.

In addition to the regulations, our internal policy outlines our core principles for animal welfare. This policy requires work done by us or on our behalf meets all applicable laws, rules and regulations governing the care and welfare of animals. 

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We understand that animal research is a sensitive subject for many people. That’s why we make it our policy to be as open as possible about our approach to animal research and animal welfare. 

We consider all legitimate and justifiable concerns about animal welfare that are raised by law-abiding individuals or organisations. However, since we conduct animal research according to the law and our internal policy, we will not tolerate any intimidation, harassment or acts of violence towards our workers or their families.

GSK public policy update: Responsible care and use of animals (PDF-203KB)

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