A drug that patients normally take during cancer therapy may have the power to increase the human lifespan, a new study reveals. Researchers in Germany say rapamycin can cause side-effects when patients take it as a lifelong anti-aging treatment. However, their new report finds even brief usage can have a dramatic impact on longevity while cutting down on side-effects.

Rapamycin is a cell growth inhibitor and immunosuppressant that people normally take while undergoing cancer treatment or after receiving an organ transplant. A team from the Max Planck Institute for Biology of Ageing, however, notes that the drug is also a promising anti-aging formula. Studies involving animals have found that low doses of rapamycin can extend life by preventing age-related changes in the intestines. Until now, however, scientists have looked at this drug as something patients would need to take for the rest of their lives.

"At the doses used clinically, rapamycin can have undesirable side-effects, but for the use of the drug in the prevention of age-related decline, these need to be absent or minimal. Therefore, we wanted to find out when and how long we need to give rapamycin in order to achieve the same effects as lifelong treatment," explains study lead investigator Dr. Paula Juricic in a university release.

Rapamycin treatment most effective when taken earlier in life?

The new study tested rapamycin in two short-term experiments using fruit flies and lab mice. The first treated young, adult flies for two weeks. The second treated young, adult mice (3 months-old) for a three-month period. In both experiments, the team found that rapamycin had a beneficial effect on the health of each animal's intestines during middle age.