The world's first anti-ageing pill?

A drug which is successfully used to treat diabetes could help humans to live longer and remain in good health, say scientists.

Metformin has already been shown to extend the life of animals, and now researchers have been given the green-light to test it on humans next year.

If the experiments on humans produce similar results to those on animals, it may be possible for people to live healthily into their 120s.

Professor Gordon Lithgow, of the Buck Institute for Research on Aging in California, and one of the study's advisors, believes that Metformin could also be used to slow or prevent the development of diseases related to ageing, such as some cases of type 2 diabetes and Alzheimers disease.

"If you target an ageing process and you slow down ageing then you slow down all the diseases and pathology of aging as well," he said.

"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-ageing drug would have been thought inconceivable. But there is every reason to believe it's possible."

Three products that may prove useful as you age: