Speaking from the pharmaceutical perspective, computer modelling really won’t do any good whatsoever. We really don’t understand what most of the stuff in a cell is, how it works and why, and how it interacts with everything else in it. We’ve mapped the genome, but that’s like looking atthis map and then trying to understand the traffic patterns, tv-watching habits, grocery habits and hair length of every person in every city and town in the country. We just don’t have that information.
There is a lot that can be learned about a drug/cosmetic molecule in a test tube, for sure. You can study what it dissolves in, you can expose it to light, acid, base, or even certain biological conditions like simulated blood or stomach acid, and see if it breaks apart or reacts with stuff to make something new. You can see how it will react with potential ingredients for a tablet or capsule, and get a fairly reasonable estimate of how long it will take to release the drug from the tablet when put in stomach acid.
But you can’t know whether it will kill someone if they consume it.
Animal testing is generally done for the major toxicological studies…will a rat die if it receives 1mg of the molecule? 1 nanogram? 50 grams? What kind of effects will it have on the rat’s DNA? Will it cause tumours to develop, or affect the reproduction cycle of the rat? Will offspring be born with complications? If the molecule has serious effects on a rat, that will often kill any potential it has to ever make it to human testing. Sure, rats aren’t the same as humans, but our cells, our DNA are close enough to be able to tell if the drug is a mutagen or teratogen.
As I understand it, further studies on the metabolism of the drug will happen in other animal models - dogs or primates. Only then (and years of studies, review of results and regulatory approval) can the drug be tested in healthy humans, and then eventually in symptomatic humans, etc until it reaches the market.
There have been failures - most people remember thalidomide as an example - but changes are made to they system after failures are discovered, and the system isn’t perfect, but it’s the best thing we have. Either we continue to test on animals, and eliminate 99.9% of the potential drug molecules from ever making it into a human because they are too toxic or ineffective, or we test everything on humans right away.
Will you* volunteer your child for testing? Yourself? And if your child dies because “Oops, turns out 1ng of this stuff causes heart failure…we thought it would cure acne…”, would that be ok with you? I’d much rather a rat died to find that out than a child.
Alternatively, we stop making cosmetics (which I could argue is a viable option). But do we stop making pharmaceuticals? Do we stop trying to cure the diseases that plague our species, stop trying to heal the wounds we suffer from? Some might say we should…let nature take it’s course. Frankly, I’m not willing to do that.
*hypothetical you, I’m not calling out anyone in this thread
To be clear: I don’t think all testing that has ever been done on animals has necessarily been valid. I support rigourous control and oversight of animal testing facilities, I support data review and selecting studies involving the fewest animals as possible to obtain the necessary data, as well as humane conditions for the animals (as much as possible within the scope of the study being done). I don’t think computer simulations will replace animal testing in my lifetime (and I’m in my 20s), because I don’t think the complexities of human biochemistry and toxicology will be completely understood within that time frame. I could be wrong - it would be great if I were - but even then, computers are only as smart as the person programming them. I’d still want to give the pill to a rat to see what happens before taking it myself!