A drug used to treat diabetes can delay the effects of ageing and extend lifespan - at least in mice - a new study has found.
Scientists found that lower doses of metformin increased lifespan in middle-aged male mice by about 5 per cent and also delayed the onset of age-associated diseases.
However, the higher dose of metformin was toxic and reduced the lifespan of mice. Rafael de Cabo, of the National Institute on Ageing in Baltimore, Maryland, US, said calorie restriction in laboratory animals had been shown to increase their lifespan, 'BBC News' reported.
Previous work has shown that metformin can extend the lifespan of simple organisms such as worms, but studies in flies and mammals have given conflicting evidence.
Metformin is one of the most widely prescribed treatments for type-2 diabetes, which occurs mainly in people above the age of 40. Further studies are needed to determine if metformin has any effect on human health and lifespan, said de Cabo.
"These are very promising results that need to be translated to humans via clinical studies," he said. Tom Kirkwood, associate dean for ageing at Newcastle University, said it is unclear what the study might mean for human health.
"Metformin is a well-established drug that acts on metabolism and has long been used against type-2 diabetes," he said.
"We've known for a long time that modulating metabolism in mice can extend survival and postpone age-related conditions, and there are sound reasons why this should be the case is a small, short-lived animal. "What we don't know however is whether similar effects on lifespan might be produced in humans," Kirkwood added. The study was published in the journal Nature Communications.