Animal research remains one of the most tightly regulated, ethically reviewed, and scientifically indispensable components of modern biomedicine. Nearly every major life-saving advance—from the discovery of insulin(1) to organ transplantation(2), antibiotics(3), vaccines, and today’s cancer immunotherapies(4)—relied on carefully validated studies in animal models. These breakthroughs did not emerge because animal research was convenient; they emerged because living systems behave in ways that no computer, organoid, or in vitro model can fully replicate.
What the public rarely sees is the people behind this work. The vast majority of professionals in the field chose their careers precisely because they love animals. Vivarium staff, veterinarians, veterinary technicians, comparative medicine specialists, and animal care professionals come from backgrounds in animal science, animal biology, and veterinary medicine. They enter this field not despite the involvement of animals, but because they are deeply committed to animal health and welfare. Many spend more hours each week caring for laboratory animals than they do caring for their own pets at home—providing enrichment, social housing, compassionate handling, advanced veterinary care, and highly structured environments to minimize stress.
This culture of care is reinforced by an oversight system unlike anything else in science. Modern animal research operates under the Animal Welfare Act, Public Health Service Policy, and layers of federal, state, and institutional regulations(5). Every study must be rigorously reviewed and approved by an Institutional Animal Care and Use Committee (IACUC), which includes veterinarians, scientists, and unaffiliated community members(6). Protocols cannot move forward without demonstrated necessity, justification for every procedure, humane endpoints, and proof that no alternative method could answer the scientific question. Amendments, renewals, veterinary inspections, and AAALAC International accreditation(7) enforce further accountability.
In other words, animal research is not simply regulated—it is designed around ethics, necessity, and accountability.
Yet even as oversight has strengthened, funding for core biomedical research has come under increasing pressure. Advocacy groups opposed to animal research have become more sophisticated in pushing not just ethical arguments, but fiscal ones. They often frame animal-based studies as “wasteful” or “obsolete,” ignoring biological realities and the extensive refinement already taking place. These narratives have begun influencing federal budget discussions, contributing to reductions or constraints in programs that rely on validated whole-organism models.
Recent budget cycles have seen the downsizing or underfunding of important CDC and NIH programs, including units involved in HIV surveillance and prevention(12), antimicrobial resistance tracking(13), and research preparedness for emerging infectious diseases(14). These cuts are not abstract policy shifts—they have direct consequences. Reduced surveillance capacity means slower outbreak detection. Reduced research support means fewer scientists, fewer early warnings, and delays in therapeutic development. What appears publicly as a principled push to “reduce animal use” can function, in practice, as a mechanism to weaken public health infrastructure.
The biology underlying these consequences is equally misunderstood. Drug discovery is extraordinarily difficult precisely because drugs do not act on isolated cells—they act on whole organisms with interconnected systems. Metabolism, immunity, endocrine signaling, microbiome composition, neural circuitry, chronic stress, diet, aging, and behavior all influence how a compound behaves inside the body(10). A drug that looks perfectly safe in vitro can trigger dangerous immune reactions, accumulate in tissues, cross the blood–brain barrier, or cause organ damage only visible in the context of multi-system physiology.
This is why the majority of drug candidates are screened first in vitro. Only those that show promise in cell-based assays, organoids, or microphysiological systems make it to animal studies. Removing animal research would not eliminate unnecessary testing—it would force human volunteers to absorb the full biological uncertainty that animal models currently protect them from.
The often cited statistic that “only 1% of drugs entering animal testing eventually receive FDA approval” (10) is therefore profoundly misleading. High attrition is not evidence that animals “fail.” It is evidence that drug discovery is intentionally conservative. The pipeline is designed to eliminate unsafe or ineffective compounds early. If animal studies were removed, the same 99% of failures would still occur—but in human subjects. Past tragedies such as thalidomide and the TGN1412 trial(8) demonstrate the catastrophic consequences when early biological screening is insufficient.
Emerging technologies—organ-on-chip systems, microfluidics, computational modeling, and advanced in vitro assays—are powerful refinements. They expand early screening capabilities and reduce the number of animals needed(9). But they cannot yet replicate chronic toxicity, behavior, metabolism, immune dynamics, or the interplay of multiple organ systems. These tools strengthen the pipeline; they do not replace the need for whole-organism validation.
The same is true of animal models themselves. Many have been refined and selectively bred over decades to represent specific human diseases—neurodegeneration, cancer, metabolic disorders, autoimmune disease, and genetic conditions(15). These models remain the most accurate biological systems available for understanding disease progression and evaluating therapeutics before human trials.
The public may not realize it, but the individuals who conduct this work—animal care staff, veterinarians, researchers—often advocate for reducing numbers and replacing models whenever possible. They support alternatives when scientifically validated. They push for refinement constantly. What they oppose is a policy environment that ignores biological complexity and jeopardizes patient safety by dismantling essential research infrastructure.
Defunding validated biomedical research—especially whole-organism research—carries a hidden human cost. It slows discovery. It weakens preparedness. It increases risk. And it shifts the burden of uncertainty away from test systems and directly onto patients, volunteers, and communities.
Responsible animal research, carried out by people who care deeply about animals and governed by rigorous oversight, remains a cornerstone of medical progress. Alternatives will continue to evolve and strengthen the scientific pipeline. But they do not eliminate the need for integrated biological systems. The future of public health depends on protecting—and properly funding—a balanced, evidence-driven research ecosystem that values both human safety and animal welfare.
1 Bliss, M. The Discovery of Insulin. University of Chicago Press, 1982.
Starzl, T. et al. “The history of organ transplantation.” Journal of the American College of Surgeons, 2000.
Fleming, A. “On the antibacterial action of cultures of a penicillium.” British Journal of Experimental Pathology, 1929.
Allison, J. “Immune checkpoint blockade in cancer therapy.” Nature Medicine, 2015.
U.S. Department of Agriculture (USDA). Animal Welfare Act and Regulations. APHIS.
NIH Office of Laboratory Animal Welfare (OLAW). Public Health Service Policy on Humane Care and Use of Laboratory Animals.
AAALAC International. Accreditation Program Description and Standards. 2024.
Expert Scientific Group on Phase One Clinical Trials. “Final Report on the TGN1412 Incident.” UK Department of Health, 2006.
Marx, U. et al. “Biology-inspired microphysiological systems.” Nature Reviews Materials, 2016.
Collins, C. et al. “Drug attrition rates and the role of preclinical models.” Nature Reviews Drug Discovery, 2022.
Hartung, T. “Human microdosing and its limits in safety testing.” ALTEX, 2017.
CDC. Impact of Budget Reductions on HIV Prevention Programs. Centers for Disease Control and Prevention, 2023.
CDC. Antimicrobial Resistance Threats Report. Centers for Disease Control and Prevention, 2019 & 2022 updates.
Congressional Research Service. Federal Biomedical Research Funding Trends and Challenges, 2023.
National Academies of Sciences. “The Use of Animal Models for Biomedical Research.” National Academies Press, 2020.
NCATS (NIH). “Animal Models and Translational Science: Why They Remain Essential.” NIH, 2021.
