We all want to live healthier for longer, but despite the increase in lifespans over the past century, at some point, age inevitably catches up with us and our cells begin to make mistakes, leading to a range of diseases such as cancer and dementia. But now researchers believe they might have found something that could slow down the ageing process entirely – a cheap diabetes drug that's already being taken by millions of people.

Known as metformin, the drug has been on the market for around 60 years. But the reason scientists are so interested in it now is that, over that time, researchers have observed that the drug appears to reduce the likelihood of age-related cancers. Studies have also shown that diabetics taking metformin live longer than people who don't have diabetes – despite the fact that the condition normally takes eight years off people's lives.

"People on metformin get 30 percent less cancers, almost every cancer except maybe prostate cancer. There are fewer studies, but there is a signal that metformin prevents cognitive decline," co-leader of the study Nir Barzilai, from the Albert Einstein College of Medicine, told Andrea Alfano from Tech Times. "Additionally, there is a study that suggests that people on metformin who, when they start taking metformin, are more obese and sicker than people without diabetes, they outlive people without diabetes." 

Based on these observations, the Food and Drug Administration (FDA) has now green-lit the drug to be trialled for its anti-ageing properties as early as next year. And if it ends up being approved, it'll be the first time that the FDA recognises ageing itself, rather than a specific disease, as a drug target.

Of course that's a big "if", and the results of the trial won't be out for years, so don't get too excited just yet. But evidence in animals suggests that they just might be onto something.

For example, after testing the drug in the roundworm C. elegans, researchers in Belgium found that the worms not only aged slower, but they stayed healthier for longer. 

And mice treated with the drug had their lifespan increased by almost 40 percent, with signs that they stayed more youthful for longer too. In humans, that would be equivalent to us living closer to 120 years old than 80. 

To be clear, the drug isn't intended to stave off death forever – it might simply put the brakes on the ageing process to keep people healthier for longer. It's thought to work by increasing the number of oxygen molecules released into a cell, although scientists aren't quite sure how that could be slowing down cellular ageing just yet. If the anti-ageing link holds up in this next trial, that'll be the next step.

The trial will be known as the Targeting Ageing with Metformin (TAME) study, and it'll involve giving either the drug or a placebo to around 3,000 elderly people who suffer from or have a high risk of developing conditions such as cancer, heart disease, and Alzheimer's.

Over the next six years, researchers will track how many patients go on to develop new age-related conditions and whether they took the drug or not. The team will also look into whether the drug appears to have impacted longevity at all.

Before you all go and stock up on Metformin, remember, we have a long wait in store for results, and there's every chance that the study will turn up no link between the drug and ageing in humans, or will produce inconclusive results.

But regardless of the outcome, this is a landmark trial for the FDA, and if things work out… well then it could be the beginning of the end for growing old before our time. Either way, we're pretty excited.