However, the lead author of the paper on the mouse study, Dr. Makoto Kuro-o, said that it's a long way from here to there. Humans do have nearly the same version of the Klotho gene that mice have, and "some studies show that variations of the Klotho gene are associated with extended life in humans," Kuro-o said.

Studies in the US have shown that people who carried two copies of a less-common form of the gene tended to die earlier than those who had the more common gene.

In the new study, a group led by Kuro-o, now an assistant professor of pathology at the University of Texas Southwestern Medical Center at Dallas, created transgenic mice with overactive versions of the Klotho gene. As a result, those mice proved to have life spans 20 percent or more longer than mice with the ordinary version of the gene, Kuro-o said.

"These are still animal experiments, but potentially it might be possible to use the hormone in humans," he said. "But we still don't know if the protein can be used to extend life span in humans."

Read More At Forbes - "Is a Longevity Vaccine on the Way?"