Scientists from the U.S. and Australia have discovered a way to reverse the ageing process. Researchers from Harvard Medical School and University of New South Wales said they have tested the procedure on mice and it proved to be successful. They are now working to test the method on humans.

In their two-year study, scientists discovered and concocted the nicotinamide mononucleotide (NMN), an "elixir" that would not only pause and rewind ageing, but could also cure cancer, type 2 diabetes as well as muscle wasting and inflammatory diseases.

The good news - the elixir could prove to be useful within five to ten years. The bad news - not everyone can afford it, because one gram alone already costs $1,000.

To demonstrate costs, researchers said an average 86 kilogram man would need to shell out $43,000 a day to enjoy the elixir, while an average 71 kilogram woman, $35,000 a day.

Scientists used two-year-old mice for the procedure. The animals were given a compound over a week, which reversed ageing to that of a six-month-old mouse.

Harvard Medical School and University of New South Wales researchers said that when applied to 60-year old human, the process could yield results that could transform to feel like a 20-year-old.

"The ageing process we discovered is like a married couple: when they are young, they communicate well, but over time, living in close quarters for many years, communication breaks down," UNSW professor David Sinclair, based at Harvard Medical School, said. "And just like a couple, restoring communication solved the problem."

"Scientists have been wondering what causes ageing for centuries," Mr Sinclair said. "We generally agree that one of the main causes is a loss of mitochondria, the cell power packs. We all know about chromosomes, but we often forget we have another set of chromosomes - in mitochondria."

Dr Nigel Turner, senior research fellow at UNSW and the study's co-author, told Guardian Australia the rate of the mice's age reversal was "amazingly rapid."

"We mapped the pathway to ageing carefully, but it was a real surprise to see the markers of ageing move back so quickly in just a week," he said.

The "frontier research," Mr Sinclair said, isn't meant to evade the tomb and live forever.

"This is not research that will keep people older for longer ... what we're trying to do is keep people out of nursing homes. What we see from the study so far is that these molecules keep the animals younger for longer and free of disease."

"It's worth pursuing, it's extending our health span, not just our life span."

Scientists have yet to see if the elixir would prove successful on humans without any negative consequences.

Mr Sinclair it would be a year to conclude if the NMN molecule trial on humans was safe and successful. Approval to manufacture and market the drug for humans could still take years, he added.