The European Chemicals Agency (ECHA) has released its sixth report on the use of alternatives to animal testing under the REACH Regulation. Published every three years, this report provides one of the most comprehensive snapshots of how regulatory toxicology is evolving towards modern, non-animal approaches.

The overall message is encouraging: alternative methods continue to expand across chemical safety assessment. However, the report also makes it clear that the transition is far from complete. For many complex toxicological endpoints, animal studies remain a regulatory requirement because scientifically validated replacements are still unavailable.

The good news: alternatives are becoming the norm

Perhaps the most important finding is that companies continue to rely more on adaptation strategies than on generating new experimental animal data.

These adaptations include:

• Read-across from structurally similar chemicals
• Weight-of-evidence approaches
• QSAR (Quantitative Structure–Activity Relationship) models
• Data waiving where sufficient scientific justification exists

Rather than conducting new animal studies by default, registrants increasingly integrate existing evidence to satisfy REACH information requirements. This reflects one of the core principles of REACH: vertebrate animal testing should always be the last resort.

In vitro methods have transformed some endpoints

The report also highlights remarkable progress in the acceptance of New Approach Methodologies (NAMs).

For endpoints such as:

• skin irritation,
• skin corrosion,
• serious eye damage, and
• eye irritation,

validated in vitro methods have become the predominant source of regulatory information.

This represents one of the greatest success stories in modern toxicology. Two decades ago, these endpoints relied almost exclusively on animal testing. Today, validated cell- and tissue-based methods provide scientifically robust information while substantially reducing animal use.

Why are animals still used?

Despite this progress, the report reminds us that not every toxicological question has a reliable non-animal answer.

Endpoints involving complex biological processes—such as repeated-dose toxicity, reproductive toxicity, developmental toxicity, carcinogenicity and certain aspects of systemic toxicity—still present significant scientific challenges.

These effects involve interactions between multiple organs, metabolism, endocrine regulation and long-term physiological responses that current standalone NAMs cannot yet fully reproduce.

This does not mean innovation has stalled. Instead, it highlights the need to integrate multiple complementary approaches—including in vitro systems, computational models, exposure science and mechanistic toxicology—rather than expecting a single method to replace every animal study.

Regulatory science is evolving

One aspect often overlooked is that replacing animal tests is not simply a scientific challenge—it is equally a regulatory one.

Before any new methodology can replace an established OECD test guideline, regulators must be confident that it provides reliable, reproducible and fit-for-purpose information for decision making.

Validation therefore requires:

• reproducibility across laboratories,
• defined applicability domains,
• transparent performance standards,
• international harmonisation, and
• regulatory acceptance.

This rigorous process explains why scientific innovation and regulatory implementation often progress at different speeds.

Data sharing continues to reduce unnecessary testing

Another important achievement highlighted by ECHA is the continued use of data sharing among registrants.

REACH requires companies registering the same substance to jointly use available information whenever possible. This avoids unnecessary duplication of studies and has prevented countless new vertebrate tests over the past decade.

Combined with read-across and computational approaches, data sharing remains one of the most effective mechanisms for reducing animal use without compromising chemical safety.

Looking ahead

The future of regulatory toxicology is unlikely to be defined by a single revolutionary technology.

Instead, it will depend on integrated testing strategies that combine:

• human-relevant in vitro models,
• computational toxicology,
• artificial intelligence,
• exposure modelling,
• mechanistic understanding through adverse outcome pathways (AOPs), and
• systematic evaluation of existing evidence.

The scientific community is gradually moving from replacing individual animal tests toward replacing entire testing paradigms.

Final thoughts

ECHA’s 2026 report shows that Europe continues to make meaningful progress in reducing reliance on animal testing. Alternative methods are no longer emerging technologies—they are already embedded within many areas of regulatory chemical assessment.

Nevertheless, important scientific and regulatory challenges remain before complex systemic endpoints can be assessed entirely without animal studies.

For toxicologists, regulators and method developers alike, the report reinforces an important message: advancing non-animal methods is not solely about developing new technologies. It also requires rigorous validation, transparent evidence generation and international regulatory collaboration.

As regulatory toxicology continues to evolve, the future will almost certainly rely on integrated, human-relevant approaches that improve both scientific quality and animal welfare.

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Further reading

The full ECHA report, The Use of Alternatives to Testing on Animals for the REACH Regulation (2026), provides a detailed analysis of registration data, regulatory trends and ECHA’s ongoing efforts to promote the development and implementation of alternative methods. Available at: https://echa.europa.eu/documents/d/guest/1173_report_use_of_alternatives_to_animal_testing_2026#msdynmkt_trackingcontext=94bf0533-d9c7-4a08-a1c3-9a78cad80200 access 07.07.2026