For decades, the U.S. FDA has expected sponsors of drug and biological products to conduct animal testing before proceeding to phase one clinical trials. That began to change in 2022, when Congress passed the "FDA Modernization Act 2.0." Although the law did not outright bar the use of animal testing, it provided an alternate route for sponsors to assure their products are ready for human studies. Specifically, it allowed sponsors to instead use "cell-based assays, microphysiological systems, or bioprinted or computer models." In parallel, Congress passed the "Modernization of Cosmetics Regulation Act." There, too, lawmakers expressed their intent to move away from animal testing, stating "[i]t is the sense of the Congress that animal testing should not be used for the purposes of safety testing on cosmetic products and should be phased out with the exception of appropriate allowances."

Shifting away from animal testing remains a congressional priority in the new year. In December 2025, the "FDA Modernization Act 3.0" was unanimously passed in the Senate. The proposed legislation, if enacted, would build upon its predecessor by requiring FDA to promulgate an interim final rule allowing the use of animal testing alternatives when evaluating investigational products.

Also pending before Congress is the "Humane Cosmetics Act of 2025," which proposes a wholesale ban on the use of animal testing when developing new cosmetics in the United States. Furthermore, if enacted, the law would bar the sale of cosmetic products developed or manufactured with animal testing, which would close the loophole permitting products animal-tested overseas to be sold to American consumers.

The U.S. executive branch has likewise been heavily involved in the promotion of animal testing alternatives. Last April, FDA announced its intent to replace animal testing when developing certain monoclonal antibodies (MABs). These new testing options, called New Approach Methodologies (NAMs), are designed to improve product safety, accelerate review times, and promote animal welfare. The agency hopes, in turn, that NAMs will also result in decreased drug prices. Examples of NAMs include AI-based computational modeling, human organ model-based lab testing, and real-world data. To facilitate biologics developers transition to NAMs, FDA released a draft guidance in December titled "Monoclonal Antibodies: Streamlined Nonclinical Safety Studies." It outlined, among other things, how sponsors can minimize, or completely forego, the use of animal testing when assessing MABs toxicology profiles. In that same vein, the National Institutes of Health opened a new division, called the Office of Research Innovation, Validation, and Application, to reduce the use of animal testing across the agency's biomedical portfolio.

These changes make clear that FDA and U.S. lawmakers have started taking concrete steps to significantly reduce the reliance on animal testing going forward. Accordingly, it is becoming increasingly important that companies develop plans to integrate animal testing alternatives into their research and development processes.