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Recent initiatives from federal agencies in the United States show growing momentum towards a reduction in the reliance on animal testing and progress in human-relevant research methods.
These are encouraging developments and reflect rising recognition of the need for modern approaches to science. However, the latest figures on animal testing in the U.S. also highlight the importance of ensuring this progress leads to meaningful reductions in the use of animals in science.
The U.S. Department of Agriculture (USDA) recently released its 2025 animal use statistics, reporting that 751,355 animals were held or used for scientific purposes in the United States. This included 42,026 dogs, 12,632 cats, 106,430 non-human primates, and 108,741 rabbits. While overall numbers declined slightly compared to 2024, cat numbers increased by 5.2% and primate numbers rose by 1.5%.
Importantly, USDA reporting does not include mice, rats, birds, or fish – the species most commonly used in experiments. We estimate that more than 14 million animals are used in U.S. laboratories each year, making the United States one of the world’s largest users of animals in science.
Several recent federal initiatives are intended to help address this challenge.
The National Institutes of Health (NIH) recently established the Office of Research Innovation, Validation, and Application (ORIVA), a significant step toward accelerating the development and use of human-based research technologies. ORIVA is intended to support NIH-wide efforts to develop, validate, and increase the use of non-animal approaches.
This announcement follows the recent publication of the NIH’s 2027–2031 Strategic Plan, which we submitted comments on, urging the agency to more explicitly incorporate human-relevant, non-animal methodologies throughout its research strategy and funding priorities.
Similar efforts are underway at the Food and Drug Administration (FDA). The agency recently released draft guidance on the use of New Approach Methodologies (NAMs) in drug development. The guidance encourages the use of human-relevant, fit-for-purpose approaches, and provides greater flexibility for companies seeking to use non-animal methods in regulatory submissions.
The guidance builds on the FDA’s efforts to advance the use of non-animal methods, including its recently published roadmap for reducing animal testing in drug development. We submitted comments supporting the guidance, whilst also encouraging the FDA to take additional steps to accelerate adoption. These steps include providing more specific guidance on non-animal methods and strengthening alignment with international regulatory standards.
The Environmental Protection Agency (EPA) has also recently announced additional actions to expand the use and acceptance of non-animal approaches in chemical and pesticide safety assessments, alongside renewed efforts to eliminate testing on mammals by 2035.
Why Congress Must Act
These agency initiatives are encouraging, but lasting change requires legislative action. Embedding these commitments in law would help ensure that progress continues regardless of future political and administrative changes. The Replace Animal Tests Act (HR 6660) and the HEARTS Act (HR 1291) would help turn promising initiatives into lasting policy.
The Replace Animal Tests Act would improve transparency and accountability by requiring federal agencies to collect and report data on animal testing, and to ensure that approved non-animal methods are used when available. The HEARTS Act would modernize federally funded research by prioritizing human-relevant science and creating incentives for researchers to adopt non-animal approaches.
Importantly, the HEARTS Act would establish a permanent federal center dedicated to advancing non-animal research through coordinated funding, training, and inter-agency collaboration. The bill would also improve transparency and accountability by requiring the collection of data on animal use and the development of strategies to reduce reliance on animals in research.
By creating a congressionally authorized NIH center focused on alternatives to animal use, the HEARTS Act would help protect the progress being made through the NIH’s new ORIVA office. Unlike administrative initiatives, which can be quickly undone by future administrations, a statutory center established by Congress would provide a durable foundation for long-term investment in human-relevant science.
Together, these bills would help transform promising agency initiatives into concrete policy, strengthen accountability and oversight of animal use, improve transparency, and accelerate the transition toward more effective, human-relevant science.
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