Researchers Find Lower Mortality Risk Among Older Women Taking Metformin

A widely used diabetes medication may also help some women live longer, according to new research on metformin. Scientists report that older women with type 2 diabetes who started metformin therapy were more likely to reach age 90 than those who began treatment with another commonly prescribed drug.

The study, published in 2025, analyzed health records from a long-running US cohort of postmenopausal women. Researchers from the US and Germany focused on 438 participants aged 60 and older, half of whom were prescribed metformin while the others received sulfonylurea medications.

Over an average follow-up period of 14 to 15 years, women in the metformin group had a 30 percent lower risk of dying before age 90 compared with those treated with sulfonylureas. The researchers described this as increased odds of achieving what they termed “exceptional longevity.”

How Metformin Might Affect Aging

Metformin has been prescribed for type 2 diabetes for decades and is known to improve insulin sensitivity and blood sugar control. In recent years, it has also attracted attention as a potential gerotherapeutic, a drug that could slow biological aging and age-related damage.

Laboratory and animal studies suggest that metformin may reduce DNA damage, suppress chronic inflammation, and influence cellular energy pathways associated with longevity. Some research has linked the drug to fewer cardiovascular events, lower cancer risk, and reduced cognitive decline in people with diabetes.

Other studies have suggested that metformin might reduce the risk of long COVID and slow neurodegeneration, although evidence remains mixed. The new findings add to this growing body of research by specifically examining survival to very old age in a real-world population.

Important Limits and Unanswered Questions

The authors stress that their analysis cannot prove that metformin directly caused longer life. Unlike randomized controlled trials, participants were not randomly assigned to each medication but instead treated according to medical advice, which can introduce bias and hidden confounding factors.

The study did not include a placebo group, and the sample size of 438 women remains relatively modest for research focused on longevity outcomes. In addition, the analysis was limited to postmenopausal women in the US aged 60 and older, meaning the findings may not apply to men, younger adults, or people without diabetes.

There are also known sex differences in type 2 diabetes risk and complications, with women often experiencing a higher cardiometabolic burden at diagnosis. Women with diabetes additionally tend to face a greater relative mortality risk than men, which could influence how strongly they benefit from particular treatments.

What Comes Next for Geroscience?

One strength of the study is its unusually long follow-up period, which tracked participants from later adulthood to age 90 and beyond. The researchers note that such extended observation is difficult to achieve in standard clinical trials, which are typically shorter and more expensive.

The findings support the “geroscience hypothesis,” the idea that biological aging can be slowed and that targeting aging mechanisms may delay multiple chronic diseases simultaneously. Metformin remains one of the leading candidate drugs being investigated as a practical longevity intervention.

Several clinical programs, including the proposed TAME (Targeting Aging with Metformin) trial, aim to determine whether metformin can delay the onset of age-related diseases in older adults at elevated risk. Until large randomized trials are completed, however, experts caution against using the drug solely for anti-aging purposes without a clear medical indication.

As populations around the world continue to age rapidly, researchers are searching for safe and affordable ways to extend healthy years of life rather than simply prolong survival. For now, metformin remains a cornerstone treatment for type 2 diabetes, while the new findings suggest that its benefits for some women may extend well into later life.