Cheap pills for dogs could be the key to anti-aging for humans.

Researchers are testing the drug rapamycin on dogs to see if it can help them live longer and healthier lives. If successful, the same treatment could be adapted for humans. The drug has been used for decades in humans who've received a kidney transplant and more recently, drug developers have discovered it can also help with certain treatment-resistant cancers. Aging experts say life extension doesn't have to be pricey, and could cost only a few bucks per pill.