How Does the NIH Initiative to Prioritize Human-Based Research Affect Research Proposing the Use of Laboratory Animals?

In July 2025, NIH announced it will no longer develop new funding opportunities focused exclusively on animal models of human disease. Rather, going forward, new funding opportunities will be designed more broadly with language that also encourages various approaches be considered. This means researchers may choose any model they deem appropriate – including a combination of approaches – to answer a research question when submitting applications seeking NIH support. This strategy is intended to open the possibilities of which types of models can be submitted in response to funding opportunities, not be restrictive or prescriptive.  

Applicants may continue to propose research exclusively involving human participants (like clinical trials), particular laboratory animals, real-world data, in vitro methods, mathematical models, artificial intelligence, in silico approaches, other alternative approaches, or a combination of models. Peer reviewers will assess, through our fair and impartial review process, the merit of each approach proposed, its relevance to human disease, and if it is best suited to answering the research question that advances biomedical research and discovery. Our overarching goal is to accelerate progress, encourage innovation, and ultimately improve the quality and validation of new approach methodologies. 

We are also prioritizing human-based technologies and models, where scientifically valid and justified. Likewise, funding opportunities will indicate a special emphasis on human-based approaches.  

These steps should encourage investigators to choose the best models for their research without constraints. To reiterate, NIH will continue to support grants that use laboratory animal models if scientifically appropriate, justifiable, and with appropriate animal welfare oversight. Moreover, if laboratory animals are proposed, scientists must still continue to clearly explain why they are necessary for their research, that the minimal number needed to ensure rigorous and reproducible studies will be used, and why the study cannot be done using another model or approach (see more here). 

While traditional animal models continue to be important to advancing scientific knowledge, NIH recognizes that prioritizing new and emerging human-based technologies can offer unique strengths to expand the toolbox for researchers to answer previously difficult or unanswerable biomedical research questions. It also moves us toward our continued long-term goal of reducing, refining, and replacing the use of laboratory animals in NIH-supported research.  

Resources 

• NIH Director’s Statement 
• NIH Director’s Desk Podcast: The Future of Animal Models in Research 
• Extramural Nexus article