Anti-ageing pills could be a reality:

But anti-ageing drugs could be closer than we think, according to international genetics and ageing expert Dame Linda Partridge.

In fact, a drug already licensed to treat cancer is getting the results scientists are after in animals.

Prof Partridge, the director of the Institute of Ageing at University College London, said when mice were fed the drug rapamycin they lived longer.

But the drug also offered protection against neurodegenerative diseases, which are closely aligned with ageing.

"Ageing is the main risk factor for all these horrible killer and chronic conditions - dementia, cardiovascular disease, cancer," Prof Partridge said.

"What we are trying to do here is hit the underlying ageing process itself through understanding mechanisms to protect against all these things at once, rather than treating them piecemeal.

"Rapamycin is beginning to look like a proof of principle that that kind of approach is going to work."

How rapamycin works is based on studies dating back decades that showed mice forced to eat smaller amounts of food not only lived longer, but experienced better health as they aged.

These animals were less likely to get cancer, heart and kidney disease and had better immune systems and cognitive power for longer.

Prof Partridge said although this knowledge had been around for a long time it was only in recent years that scientists began to unravel the molecular reasons behind how dietary restriction worked.

It turned out a network of molecules that senses nutrients in the body, involving insulin, amino acids and cellular energy, was responsible.

The aim has been to develop a treatment to derive the benefits of diet restriction, without actually going on a diet.

Rapamycin works by inhibiting a powerful molecule in this whole nutrient-sensing network, Prof Partridge said.

However, the drug - a natural product initially discovered in the soil of Easter Island - has its downside.

It's an immune suppressant and is also used to prevent the body rejecting an organ after transplant.

But there's potential to boost the drug's health benefits while minimising its undesirable side effects, Prof Partridge said.

Other approaches under investigation to lessen the impact of ageing involve recycling old drugs for new uses, such as aspirin, Prof Partridge said.

The common analgesic is the subject of multiple studies which have shown it could protect against heart disease and various cancers.

"A lot of drugs have a much wider therapeutic range than we'd suspected," said Prof Partridge, who is also the founding director of the Max Planck Institute for the Biology of Ageing in Cologne.

"Some reusing of existing drugs as well as development of new ones may well accelerate this kind of approach to human health," Prof Partridge said.

Lifestyle factors including diet and exercise are obviously an important part of staying well while ageing, Prof Partridge said, but it was difficult to get people to modify their behaviour.

"Given the impact of these ageing-related diseases, we're going to have to intervene pharmacologically."

Prof Partridge will deliver the 2012 Graeme Clark Oration on Wednesday in Melbourne.