A common diabetes drug may hold great potential to help with aging, even if scientists aren't exactly sure why.
According to a study, the drug metformin doesn't just help patients to effectively manage their type 2 diabetes.
In addition, it may also give older women a better chance of living to the grand old age of 90.
That's the finding of a study published in 2025, suggesting the medication may offer a variety of anti-aging effects.
Scientists in the US and Germany used data from a long-term US study of postmenopausal women.
Records for a total of 438 people were selected – half of whom took metformin to treat diabetes, and half of whom took a different diabetes drug, sulfonylurea.
While there are some caveats and asterisks to the study, those in the metformin group were calculated to have a 30 percent lower risk of dying before the age of 90 than those in the sulfonylurea group.
"Metformin has been shown to target multiple pathways of aging and therefore has been postulated as a drug that may extend human longevity," write the researchers in their published paper.
"We found that metformin initiation increased exceptional longevity compared with sulfonylurea initiation among women with type 2 diabetes."
Metformin has been around for decades and is considered a gerotherapeutic: a drug able to slow down various aging processes in the body.
For example, it's been shown to limit DNA damage and promote gene activity associated with long life.
Previous studies have shown that metformin can put the brakes on wear and tear in the brain and even reduce the risk of long COVID.
However, scientists aren't yet sure that the drug extends lifespan, especially in humans – which is part of the reason for this study.
This research can't prove cause and effect like a randomized controlled trial (RCT) might, though, because the participants weren't randomly assigned to one treatment or the other – rather, they were following professional advice.
What's more, there wasn't a placebo group that received no treatment. The overall sample size wasn't particularly large, either.
"Because our study was limited to postmenopausal women 60 years and older with type 2 diabetes, its generalizability to men and younger populations is unknown," the study authors caution.
"There are sex differences in type 2 diabetes, with women having a higher cardiometabolic risk factor burden at the time of diagnosis than men. Further, women with diabetes have higher risk of mortality than men."
The study also has its strengths – for example, the average follow-up period was 14 to 15 years, extending far beyond the length a standard RCT would be able to.
That's important to understand how any intervention impacts lifespan.
"A key advantage of our analysis was the long follow-up period after treatment initiation enabled by examination of a cohort with extensive follow-up from midlife to ages 90 and older, which is not feasible in typical randomized controlled trials," write the researchers.
RCTs could follow further down the line to dig deeper into these results, the researchers suggest. In the meantime, as the global population continues to skew older, studies continue to find ways to keep us healthier for longer and reduce damage to the body as we age.
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"The geroscience hypothesis posits that biological aging is malleable and that slowing biological aging may delay or prevent the onset of multiple age-related diseases and disability," write the researchers.
"A key goal of geroscience is to identify novel therapeutic and preventive interventions that slow biological aging."
The research has been published in the Journal of Gerontology: Medical Sciences.
An earlier version of this article was published in June 2025.