Which is the problem. Most new drugs don't work. Some work in some animals but not in humans. Some have side effects in humans. Some seem to work at first, but the effect doesn't last. Some have long-term side effects. Some are harmful to some part of the population. That's why so much clinical testing is required to find the ones that do work.

The gold standard of clinical testing is "better off 10 years later". Drugs have made it all the way to approval and later been pulled because they failed that test.