There is increasing interest in finding drugs, known as gerotherapeutics, that can slow ageing and help people live longer. Metformin, a common diabetes drug, is being studied because it affects several ageing-related processes.

In a multi-institutional study published online in the Journal of Gerontology: Medical Sciences on May 19, 2025, researchers examined the relationship between metformin use and a longer lifespan among postmenopausal women with type 2 diabetes. When compared with sulfonylurea, another class of diabetes medication, they reported that using metformin increased the likelihood of reaching the age of 90 or older, known as exceptional longevity.

The study's key finding is that the use of metformin is associated with a 30% lower risk of death before age 90 compared to use of sulfonylurea. However, because metformin was not compared to a placebo, future studies are needed to determine the underlying cause of this association.

Researchers analysed data from the Women’s Health Initiative (WHI), a large, national cohort study with over 30 years of follow-up, funded by the NIH.

The WHI, which recently had its NIH funding reinstated, has led groundbreaking research in women’s health since the 1990s, generating findings that have shaped clinical practice and public health policies in the United States. Some key facts about WHI:

As for the current study, led by associate professor Aladdin H. Shadyab, Ph.D., M.P.H., and distinguished professor Andrea LaCroix, Ph.D., M.P.H., at the University of California San Diego Herbert Wertheim School of Public Health and Human Longevity Science and School of Medicine, the authors note that these findings contribute to a growing understanding of metformin’s potential role in promoting human health and longevity.