Animal testing: numbers fall, heaviest burdens rise
In 2025, Switzerland used fewer animals in experiments than at any time since records began. At the same time, the number of animals in severity grade 3 rose to its highest level in 26 years.
The Swiss animal testing statistics for 2025 tell two stories that do not at first sight fit together. A total of 507,863 animals were used in experiments. That is 14,773 fewer than in the previous year and the lowest figure since record-keeping began in 1983. At the same time, the number of animals in severely burdensome experiments in the severity grade 3 category rose to 29,413 — an increase of 7.4 percent and the highest figure in 26 years.
Both figures come from the Federal Food Safety and Veterinary Office (FSVO). They do not contradict each other. They show why a total figure alone is not enough for an ethical and scientific assessment.
Fewer animals overall
The decline of roughly three percent is remarkable over the long term. Over the past two decades, according to the federal office, the number of animal uses ranged between about 520,000 and 760,000 per year. Numbers are also falling among animals bred in laboratory animal facilities: since 2021 their number has dropped by roughly a fifth.
Such developments can have several causes. These include improved study planning, alternative methods, changed research programmes or a more precise selection of models. The statistics alone cannot show which factor had how strong an effect. They do confirm, however, that the total number of animal uses in Switzerland is not simply rising steadily.
Why severity grade 3 matters in particular
Severity grade 3 denotes experiments that place a severe burden on the animal. The classification runs from grade 0 for procedures that cause no burden to grade 3 for severe burdens. In 2025, 2,033 more animals were used in this highest category than in the previous year. The increase mainly involved mice and, according to the federal office, was above all linked to additional animal uses in cancer research.
At the same time, the number of animals in severity grade 2 — moderate burden — reached its lowest level of the past ten years. If the two highest severity grades are added together, their total still declined compared with the previous year, because the drop in severity grade 2 was larger than the rise in severity grade 3.
That does not remove the ethical question. It only places it more precisely: a decline in the total number is no reason to overlook the rise in severe burdens. Conversely, a higher figure in severity grade 3 does not automatically mean that animal welfare is taken less seriously overall. For every authorisation, research must justify the specific burden and the expected gain in knowledge.
The legal standard remains strict
In Switzerland, animal experiments may be authorised only if no suitable alternative is available and the expected benefit outweighs the burden on the animals. In addition, the number of animals and the burden must be limited to what is indispensable. This principle underpins the «3Rs»: replace, reduce, refine.
The statistics do not document whether every individual decision was ethically correct. That is the task of the authorisation procedures, the cantonal commissions and oversight by the authorities. They do, however, make transparent in which research areas and severity grades animals were used. It is precisely this transparency that makes it possible to ask critical questions in a targeted way instead of arguing with a single total figure.
For the public debate, a dual finding remains: the number of animal uses is falling to a record low. The number of particularly burdened animals is rising. Both are relevant. Anyone who wants to judge progress in replacing and reducing animal experiments must therefore not only count how many animals are used, but also what burden they are exposed to and which alternatives actually become available. This also matters for research funding: alternative methods must not only be developed, but reliably validated, made broadly accessible and continuously improved.
The statistics thus also point to a research task. Anyone who wants to avoid severe burdens must anchor alternatives early in study planning, funding and assessment. Whether that succeeds cannot be read from a single annual figure, but from the development by severity grade and research area.
