Aisha Akhtar

Tamoxifen is one of the most effective treatments we have against breast cancer.

And it did undergo animal tests, but we found severe liver disease in rats only after this drug had already moved on into human clinical trials.

But if we had found it before, it likely would never have even moved on and been tested.

So we likely would have missed out on the most significant and effective breast cancer treatment we have today.

Of course.

So what we now know is that up to 95% of all drugs and vaccines that are found safe and effective in animals are shown to be unsafe or ineffective in humans.

It is such a drastic, dismal failure.

But I will say that because the evidence has been so strong about the failure rate of animal testing, we had some major developments here in the US just last year.

In 2025, both the National Institutes of Health and the US Food and Drug Administration finally acknowledged this high failure rate of animal testing.

And as a result, the NIH has made an announcement that it was going to prioritize funding for human-based testing methods, methods based on human biology.