Can a diabetes drug called metformin improve the way we age?

From weight loss to heart protection, is there anything the new wave of diabetes medications can’t do? Scientists are studying how one drug called Metformin might even halt cognitive decline and prevent cancer, writes Sabrina Rogers-Anderson.

By Sabrina Rogers-Anderson

With so-called “miracle weight-loss drugs” like Ozempic and Mounjaro getting a lot of air time for helping people shed stubborn kilos, it’s easy to forget most of them were designed to treat type 2 diabetes. Weight loss just seems to happen in the process. Talk about the best side effect ever known to man!

Ozempic is the current shining star of the diabetes drug world, but global shortages have made it hard for patients to secure their scripts.

Meanwhile, a lesser-known medication in the biguanides class is lurking in Ozempic’s shadow despite being one of the most widely prescribed drugs in the world to treat type 2 diabetes. It's called metformin.

Metformin is not only highly effective at lowering blood sugar levels, but it also has heart health benefits and can assist with weight loss.

And there’s a large body of ongoing research investigating metformin’s potential to prevent and treat a variety of other health conditions. It’s even hypothesised that metformin could slow ageing and increase life expectancy.

Keeping cognitive decline at bay

The University of New South Wales’ Sydney Memory and Ageing Study (MAS) followed 1,037 people aged 70 to 90 for 12 years to understand rates and predictors of healthy cognitive ageing, mild cognitive impairment (MCI) and dementia in older Australians. 

“There are high rates of diabetes in that population and we know that diabetes increases the risk of dementia about 3 times,” says endocrinologist and MAS researcher Professor Katherine Samaras.

“So, we investigated whether participants who had diabetes and were taking metformin developed dementia at the same rate as those who had diabetes but didn’t take metformin. At 6 years, the rate of dementia was 80% less in those who were taking metformin.”

The MAS researchers also examined participants’ rates of cognitive decline.

“People with diabetes have a much more rapid rate of cognitive decline, but participants who were on metformin had the same rate of decline as those who didn’t have diabetes,” says Katherine. “The results really suggest that metformin has a neuroprotective effect on cognitive health.”

To confirm these results, the research team is currently running a three-year, placebo-controlled trial of metformin in non-diabetic people over the age of 60 who have very mild cognitive impairment.

“We want to see if we can halt cognitive decline in people who have central [abdominal] obesity but are otherwise perfectly,” Katherine explains. “We're giving them metformin and tracking what happens to their cognitive performance, what happens metabolically and what happens in their brains with specialised scans.

“We’re hoping we’ll see the same cognitive effects as the previous study, but much earlier and in people who don't have diabetes. Metformin is very cheap - about $12 a month if you don’t meet the criteria to receive the government subsidy - so we’re very excited about the possibilities.”

Fighting cancer and turning back the clock

While some of the health marker improvements metformin users experience can be attributed to the blood sugar control and weight loss it induces, Katherine explains that the medication’s effects go beyond those you’d get from cutting dietary sugar and losing some weight.

“Metformin shifts things metabolically,” she says. “It offers cells some protection against nutrient toxicity, which is an excess of energy flooding the cells. It protects the components of the cells that allow them to survive and flourish rather than drown in the excess nutrients.”

As researchers around the world continue to investigate the potential applications of metformin, Katherine is hopeful that it will one day be approved for other conditions.

“There's more and more evidence that metformin has a whole range of benefits beyond glucose control,” she says. “That even includes some evidence of anti-cancer effects and there's also some really interesting data that Metformin improves outcomes for some types of cancer when it’s added into standard cancer therapy.

“We're also hoping to show that if it has anti-brain-ageing effects, there will be anti-ageing effects elsewhere in the body.”

Watch this space!

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