A common diabetes medication will be tested as the world's first anti-aging drug in clinical trials next year. If successful, the trials could result in people taking the medication in an effort to live healthy lives well into their 120s, researchers say.

Scientists have already proven that the diabetes drug metformin extends the lives of animals and some small studies in diabetics suggest it may do the same for people. , The latest study, approved by the Food and Drug Administration, aims to definitively determine metformin’s overall anti-aging benefits, the Daily Telegraph reports.

If successful it could mean that a person in his or her 70s who takes the drug would be as biologically healthy as a 50-year-old.

"If you target an ageing process and you slow down ageing then you slow down all the diseases and pathology of ageing as well,” said aging expert Gordon Lithgow, of the Buck Institute for Research on Aging in California, who is involve in the study.

"I have been doing research into aging for 25 years and the idea that we would be talking about a clinical trial in humans for an anti-aging drug would have been thought inconceivable. But there is every reason to believe it's possible. The future is taking the biology that we've now developed and applying it to humans."

Metformin, the world's most widely used diabetes drug, costs just 10 cents a day. Scientists say it knocks down inflammation linked to many age-related diseases and also increases the number of oxygen molecules released into a cell, which boosts vitality and longevity.

The new clinical trial called Targeting Aging with Metformin, or TAME, is scheduled to begin in the U.S. next winter. Scientists from various institutions are raising funds and recruiting 3,000 70 to 80-year-olds who have, or are at risk of, cancer, heart disease and dementia.