Ending animal testing is no longer a distant goal. A combination of new technologies, shifting regulations, and growing investment is actively replacing animal experiments with methods that are often more accurate at predicting how chemicals and drugs affect human bodies. The path forward involves advancing these alternatives, changing laws, and redirecting funding.
Why Animal Testing Still Exists
Most animal testing today serves medical research and safety testing for drugs, chemicals, and industrial products, not cosmetics. In the European Union plus Norway, 8.48 million animals were used for scientific purposes in 2022. The U.S. reported just under 800,000 animals used in 2024, but that number is a massive undercount because it excludes mice, rats, fish, and birds, which make up the vast majority of lab animals.
The core reason animal testing persists is regulatory inertia. For decades, governments required animal data before approving new drugs or certifying chemical safety. Even where bans exist, loopholes remain. The EU outlawed animal testing for cosmetics, but under its REACH chemical safety regulation, animal testing can still be mandated to assess workplace risks from certain ingredients. This means a cosmetic ingredient tested on animals under REACH rules can end up in products sold as “cruelty-free.” PETA has suspended its cruelty-free certification for some EU companies over exactly this conflict.
Technologies Replacing Animal Models
Organ-on-a-Chip
Organ-on-a-chip devices are small microfluidic systems where human cells are grown in structures that mimic actual organs. A liver chip, for example, can co-culture multiple cell types to form structures resembling real liver tissue, complete with the sinusoidal architecture that processes toxins. These chips maintain liver function over extended periods and can simulate how a whole liver responds to drug candidates. Researchers have built species-specific liver chips for humans, dogs, and rats, then used them to verify drug-induced liver injury patterns and identify damage mechanisms that vary between species. Blood-brain barrier chips, lung chips, and kidney chips also exist, each replicating the tissue interfaces where drugs cause problems.
The key advantage is human relevance. Animal organs process drugs differently than human organs, which is why roughly 90% of drugs that pass animal trials fail in human clinical trials. Organ chips built with human cells sidestep that translation problem entirely, and data from these chips has shown correlation with actual clinical trial outcomes.
3D Bioprinted Human Tissue
For skin safety testing, 3D bioprinted human skin is already replacing the notorious Draize test, which historically involved applying chemicals to rabbit eyes and skin. Researchers take fibroblasts and keratinocytes from healthy human skin biopsies and print them into layered constructs that closely resemble native skin. Some models even include melanocytes to create pigmented skin, allowing testing across different skin types.
Three printing methods are currently in use: extrusion-based, laser-assisted, and microvalve-based bioprinting. The resulting constructs are realistic enough that the OECD has established formal test guidelines for using in vitro skin models to assess absorption, corrosion, irritation, and sensitization. These aren’t experimental anymore. They’re standardized.
Stem Cell-Based Testing
Human induced pluripotent stem cells, created by reprogramming ordinary skin or blood cells, allow researchers to grow virtually any cell type in the lab. What makes this transformative is the ability to build libraries of genetically diverse cell lines that reflect the range of drug responses across a real population. Instead of testing a drug on genetically identical mice, scientists can test it on heart cells, liver cells, or brain cells derived from hundreds of different people.
Even more powerful: stem cells taken from patients who experienced rare but serious side effects from a drug can be used to screen future compounds for the same risk. This approach could catch dangerous reactions that animal models routinely miss, since those reactions often depend on specific human genetic variations that simply don’t exist in lab animals.
Computer Modeling
In silico toxicology uses computational methods to predict whether a chemical will be toxic before it touches a living cell. These models work by analyzing molecular structures, comparing them against databases of known toxic compounds, and flagging structural features associated with harm. The main approaches include quantitative structure-activity relationship models (which predict toxicity based on a chemical’s physical properties), read-across methods (which infer a chemical’s danger from similar compounds with known effects), and dose-response modeling that simulates how much of a substance causes damage at different exposure levels.
AI is accelerating this field dramatically. Models trained on massive datasets of existing toxicity results can screen thousands of compounds in hours, a process that would take years and thousands of animals using traditional methods.
Regulatory Changes Already Underway
The most significant recent shift came in April 2025, when the FDA announced a plan to phase out animal testing requirements for monoclonal antibodies and other drugs. The agency will encourage companies to submit safety data from what it calls New Approach Methodologies: AI-based toxicity models, cell lines, and organoid testing. Companies that provide strong non-animal safety data may receive streamlined review, creating a financial incentive to adopt these methods. The FDA is also launching a pilot program for select drug developers to use primarily non-animal testing strategies.
This matters because the FDA’s requirements have long been the single biggest driver of animal testing in drug development. When the regulatory agency says animal data is no longer the only acceptable evidence, the entire pharmaceutical industry shifts.
The FDA will also begin accepting real-world safety data from countries with comparable regulatory standards where a drug has already been tested in humans. This reduces redundant animal studies for drugs that are already approved elsewhere.
Where the Money Is Going
In 2025, the NIH launched an $87 million, three-year project to develop standardized organoid models, tiny lab-grown 3D tissue replicas of human organs. The Standardized Organoid Modeling Center, based at the Frederick National Laboratory for Cancer Research in Maryland, will create, test, and deploy these models nationwide, with plans to transition the technology to private industry if successful.
Standardization is the critical piece. Many alternative methods already work in individual labs, but regulators need assurance that a liver organoid grown in Boston will produce the same results as one grown in San Francisco. Without that consistency, alternatives can’t replace animal tests in formal safety evaluations. The NIH investment targets exactly this bottleneck.
The Remaining Scientific Gaps
Current non-animal methods excel at testing toxicity in individual tissues but struggle with systemic effects, the complex chain reactions that happen when a drug passes through the gut, enters the bloodstream, gets processed by the liver, and affects the heart and kidneys simultaneously. A liver chip can tell you if a drug damages liver cells, but it can’t tell you whether the liver’s processing of that drug creates a byproduct that harms the brain.
Researchers are working on multi-organ chip systems that connect several organ models through shared fluid channels, essentially building a simplified human body on a desktop. These systems are improving but aren’t yet sophisticated enough to fully replace whole-animal studies for complex systemic questions like long-term cancer risk or reproductive toxicity.
This is why most experts frame the transition as progressive rather than instantaneous. The 3Rs framework, established in the 1950s and now embedded in regulations worldwide, outlines the priority order: first replace animal use wherever possible, then reduce the number of animals in remaining experiments, then refine procedures to minimize suffering. Each new validated alternative method chips away at the list of tests that still require animals.
What Individuals Can Do
Consumer choices have real impact. The EU’s cosmetics testing ban exists largely because of sustained public pressure. Buying from companies certified cruelty-free (while being aware of loopholes like REACH) sends a market signal. Supporting organizations that fund alternative method development and lobbying for regulatory change accelerates the timeline.
Advocacy directed at regulators is particularly effective right now. The FDA’s recent policy shift shows that agencies are responsive to both scientific evidence and public demand. Contacting elected representatives about funding for non-animal research methods, supporting legislation that mandates acceptance of validated alternatives, and pushing for closure of regulatory loopholes like the EU’s REACH exemption all target the structural barriers that keep animal testing in place even when better options exist.