Unfortunately, the current testing system has serious problems. Some of these issues have long been known, such as that testing is very expensive or that it harms or kills many animals. In addition, a big problem is that testing does not work the way scientists would like.
When scientists study a chemical, they are trying to figure out whether it is safe for a person to be exposed to a small amount of the test substance for many years. Scientists are trying to answer the question of the safety of long-term exposure to a small amount of a substance. But studying long-term effects in animals is difficult because most animals don’t live long, and scientists want information much faster than an animal’s natural lifespan. So scientists expose animals to much higher doses of chemicals—the top dose in experiments usually shows some signs of an overdose.
In fact, researchers can use concentrations of the chemical that are thousands of times higher than what any human would experience in actual use. The problem is that with this approach, the effect does not appear thousands of times faster. All you can learn from high dose experimentation is what can happen in overdose situations.
Another problem with animal testing is that humans are not just giant rats, mice, rabbits, or other experimental animals. Sure, there are some key similarities in basic biology, cells, and organ systems, but there are also differences that make a big difference.
Four main factors help determine how a chemical exposure affects an animal: how the chemical is absorbed, distributed throughout the body, metabolized and excreted. These processes can vary considerably between species, sometimes leading to critical differences in the effects of chemical exposure.
Researchers are trying to use animals that are close to humans. If they are concerned about potential effects on the heart, they may use a dog or a pig – because the circulatory systems of these animals are more similar to humans than those of other animals. If they are concerned about the nervous system, they may use cats or monkeys. But even with a relatively good match, differences between species can make it difficult to translate human results. Small differences in biology can make a big difference. For example, in rats, mice and rabbits, the skin quickly absorbs chemicals – much faster than human skin. Thus, tests using these animals may overestimate the dangers of chemicals that are absorbed through the skin.
According to the US Food and Drug Administration, more than 90% of promising new compounds fail in human tests, either because the compounds don’t work or because they cause too many side effects. However, each of these compounds has previously been successfully tested in numerous animal tests.
Animal testing is time-consuming and expensive. It takes about 10 years and $3,000,000 to complete all the animal studies required to register one pesticide with the US Environmental Protection Agency. And tests for this single pesticide ingredient will kill up to 10 animals – mice, rats, rabbits, guinea pigs and dogs. There are tens of thousands of chemicals awaiting testing around the world, and testing each one can cost millions of dollars, years of work, and thousands of animal lives. However, these tests are not a guarantee of safety. As we mentioned above, less than 000% of potential new drugs successfully pass human trials. According to an article in Forbes magazine, pharmaceutical companies spend an average of $10 billion to develop a new drug. If the drug doesn’t work, companies simply lose money.
While many industries continue to rely on animal testing, many manufacturers are facing new laws that prohibit testing certain substances on animals. The European Union, India, Israel, São Paulo, Brazil, South Korea, New Zealand, and Turkey have adopted restrictions on animal testing and/or restrictions on the sale of tested cosmetics. The UK has outlawed animal testing of household chemicals (e.g. cleaning and laundry products, air fresheners). In the future, more countries will adopt these bans as more and more people object to chemical testing on animals.