The HEARTS Act of 2025 amends the Public Health Service Act to prioritize nonanimal research methods where feasible in all NIH-supported research. It creates the National Center for Alternatives to Animals in Research and Testing within NIH to fund, promote, and coordinate humane, humanbiology-based approaches.
The bill also expands oversight by requiring evaluation of nonanimal methods before any animal research proceeds and by introducing systematic searches and specialized review to ensure alternatives are considered. Finally, it mandates public reporting on the numbers of animals used in federally funded research and sets up a framework for reducing animal use over time.
At a Glance
What It Does
Requires NIH-funded research proposals to prioritize scientifically satisfactory nonanimal methods when available; establishes the National Center for Alternatives to Animals in Research and Testing to fund, promote, and coordinate nonanimal methods; mandates evaluation of nonanimal methods before approving animal research and requires thorough searches for alternatives.
Who It Affects
NIH researchers, universities and research institutes receiving federal funds, and proposal reviewers; developers of nonanimal methodologies.
Why It Matters
Creates a formal pathway to shift research toward human-relevant models, increases transparency of animal use, and builds infrastructure to sustain nonanimal innovation.
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What This Bill Actually Does
The HEARTS Act is a comprehensive push to move biomedical research toward nonanimal methods whenever those methods can reasonably obtain the same results. It establishes a National Center for Alternatives to Animals in Research and Testing within the NIH to fund, train, and connect researchers who are developing human biology–based models such as organoids, microphysiological systems, and AI-driven simulations.
The bill also tightens the process for animal-based research by requiring a full evaluation of nonanimal options before any animal work is approved, and by ensuring review panels include experts in nonanimal methods and librarians who can verify the thoroughness of searches for alternatives. In addition, the Act adds reporting requirements to publicly disclose the number of animals used in federally funded research and to track progress toward reducing animal use over time.
The Five Things You Need to Know
The bill requires NIH to prioritize scientifically satisfactory nonanimal methods in all feasible proposals.
It creates the National Center for Alternatives to Animals in Research and Testing within NIH.
Before approving any animal research, the proposal must demonstrate that all viable nonanimal methods have been evaluated.
Research proposals must be reviewed by experts in nonanimal methods, with access to specialized librarians for thorough searches.
Federally funded entities must report animal usage every two years and publish plans to reduce animal use.
Section-by-Section Breakdown
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Short Title
This Act may be cited as the Humane and Existing Alternatives in Research and Testing Sciences Act of 2025 (the HEARTS Act of 2025). The designation signals Congress’ intent to formalize a pathway toward humane, nonanimal research options within NIH-supported work.
Findings
Congress outlines the rationale for the shift to nonanimal methods, highlighting the large numbers of animals used historically and the variability in translational success from animal models to human outcomes. It emphasizes the existence and growth of human-relevant alternatives and notes the current gaps in oversight and data sharing that hinder reducing animal use. The findings set the stage for a new center and new requirements intended to drive more humane, effective research.
Animals in Research: Revisions
Section 495 of the Public Health Service Act would be redesigned to require a comprehensive, nonanimal-method-first approach. It adds a duty to establish guidelines that require researchers to identify nonanimal methods and to ensure, before animals are used, that viable alternatives have been fully evaluated. It also mandates reviews by at least one nonanimal-method expert and access to a librarian skilled in locating nonanimal resources. The section also requires a formal process to search for nonanimal alternatives and to document that process in research proposals.
National Center for Alternatives to Animals in Research and Testing
The Act creates a National Center for Alternatives to Animals in Research and Testing within NIH. It expands the NIH institutes and centers roster and assigns the Center the duties of funding, training, and coordinating nonanimal methods, building cross-institution collaborations, and collecting and publishing data on animal use in federally funded research.
Reporting on Animals Used in Federally Funded Research
A defined set of reporting obligations directs each covered entity to disclose the number of animals used in federally funded work, disaggregated by species, with initial reporting due within two years of enactment and biannual updates thereafter. The data must be publicly accessible, and entities must also publish a plan outlining steps to reduce animal use, contributing to a transparent, measurable reduction trajectory.
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Explore Science in Codify Search →Who Benefits and Who Bears the Cost
Every bill creates winners and losers. Here's who stands to gain and who bears the cost.
Who Benefits
- NIH-funded researchers who adopt nonanimal methods gain access to dedicated funding and incentives to develop and validate these approaches.
- Nonanimal-method developers and vendors benefit from increased funding opportunities and collaboration networks to bring organoid, microphysiological, and computational models to maturity.
- Universities and research institutions that train and support investigators in nonanimal methods gain clearer pathways and resources for modernizing research programs.
- Public health stakeholders and clinicians benefit from human-relevant models that potentially improve translational accuracy and patient outcomes.
- The public benefits from greater transparency on animal numbers and progress toward reducing animal use in federally funded research.
Who Bears the Cost
- Researchers and institutions transitioning away from traditional animal models may incur upfront costs for training, validation, and acquiring new equipment.
- Federal agencies funding research will bear costs associated with establishing and sustaining the National Center for Alternatives and the expanded oversight requirements.
- Institutions with existing animal facilities may need to reallocate budgets and resources to support nonanimal method development and implementation.
- Reviewers and librarians will require training and time to adjudicate nonanimal method searches and provide expert input.
- Administrative costs rise due to new reporting requirements and public data dissemination obligations.
Key Issues
The Core Tension
Balancing the imperative to reduce animal use with the equally important need to preserve scientific rigor and timely research, especially in fields where nonanimal methods are still maturing or lack full translational validation.
The HEARTS Act presents a principled shift toward humane, human biology–based research models, but it raises practical questions about timelines, funding, and the readiness of nonanimal methods to supplant animal work in all contexts. While the bill provides mechanisms to incentivize and fund nonanimal methods, its success hinges on the availability and maturity of viable alternatives and the willingness of researchers and institutions to adopt new practices.
Ensuring that the evaluation of nonanimal methods does not bottleneck important research will require careful implementation, clear milestones, and ongoing funding.
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