A study team led by researchers at the National Institute on Aging has found that diabetes pill- metformin- can extend lifespan.
The research was conducted on a set of male mice which lived longer than average when given metformin. Scientists tested two doses of the drug and found that the higher dose was toxic.
Metformin is either used alone or with other medication in diabetes type-2 where the body doesn't use insulin normally.
Male mice on 0.1 percent metformin had 5.83 percent increase in lifespan when compared with mice that weren't given the drug (control group). Higher dose of the drug (1 percent metformin) was associated with 14 percent shorter lifespan, most probably due to kidney failure.
Researchers have also looked at other drugs/compounds that can aid longevity. A previous study had found that resveratrol- a compound found in grapes and nuts- can improve health, but not longevity.
"There is increasing interest in exploring how drugs for one use might be repurposed for another," said Richard J. Hodes, M.D., director of the NIA, according to a press release. "It is exciting to discover that a drug already known to be safe and effective in humans might be further studied for a possible, alternate use for healthy aging."
People have been using metformin since 1960 and other studies on the drug have shown that it can also be used to treat cardiovascular diseases, polycystic ovarian syndrome, cancer and cellular immunity.
"Aging is a driving force behind metabolic syndrome and diabetes. Given that metformin is clinically proven to alleviate symptoms of these conditions, and reduce risk of cancer, we thought perhaps it was a good candidate to study for its broader effects on health and lifespan," Rafael de Cabo, Ph.D., at the NIA's Intramural Research Program.
The team focused on drugs that can mimic calorie-restriction in the body. Diets with fewer calories have known to extend life and protect brain from damage by changing the way the body uses energy. Metformin can induce similar changes in the body.
In the study, mice were given either 0.1 percent, 1 percent or no metformin. They found that mice on 0.1 percent metformin weighed less than the other mice, though these mice ate more than others.
Study results also showed that mice on metformin had low incidence of cataract or metabolic syndrome. The mice' livers also showed signs of being on low-calorie diet, which led to genetic activity that prolongs life.
Researchers said that more research would be required before the drug could be used in human trials.
The present study is published in the journal Nature Communications.