Dont kill em
Animals shouldn't be experiments
Animals react differently
Animals have diverse and completely different reactions to these products than humans do. Animal tests are most of the time unreliable because our metabolisms and cells are completely different, which is why its a waste of lives, money and time.
Testing on animals is completely cruel and abusive
Animals are forced to be fed unknown substances and chemicals that contribute to the experiment. They are held captive under horrible conditions, left without food and water. The burns and wounds caused by the experiment are left to study, the healing process. Pain is often left to study the effect and remedies. Animals aren't given any type of pain reliever. Of course after being done experimenting on them they are left to die. ANIMALS ARE LIVING THINGS TOO, JUST BECAUSE THEY CANT COMMUNICATE DOESN'T MEAN THEY DONT SUFFER AND FEEL THE PAIN.
Alternatives
Its the 20th century and technology is advanced enough to create better methods to investigate and experiment. Studying human cells is actually a better alternative. Cells are grown in tubes and plastic wells that produce better results than on animal skin without harming the animals. Another alternative is virtual molecules which are processed and formed in the computer, the molecules can detect the toxicity of substances without having to experiment on animals