When Associate Professor Yoror Barak and his team at the University of Otago began reviewing a decade of research on metformin, they expected to confirm what many already suspected: that the common type 2 diabetes drug offered protective benefits for the heart and brain. What surprised them was what they found in the prostate.
Analyzing data from 2.25 million patients with type 2 diabetes across studies spanning the past ten years, the researchers discovered that metformin use was associated with a reduced risk of death, cardiovascular disease, and dementia — outcomes the team had anticipated. The unexpected finding, published in Rejuvenation Research, was a significant reduction in prostate cancer rates among those taking the medication.
"Metformin has been widely researched as an 'anti-aging' drug, but our analysis is exciting as the role of metformin in reducing cancer rates has been proposed prior to this project, but never in relation to prostate cancer," Barak said. "It is interesting to find an unexpected benefit from taking the drug."
The discovery adds another dimension to what researchers already knew about metformin's potential. While the findings are promising, Barak emphasizes it is too early to recommend the drug for nondiabetic individuals. However, he believes metformin should become a standard part of type 2 diabetes management for males.
"This is one way medical professionals can contribute to a better future for people struggling with type 2 diabetes," he said.
The research arrives at a pivotal moment for Aotearoa New Zealand. According to World Health Organization projections, the nation will officially become an "aging society" in the late 2030s. Barak argues that this timeline makes investments in longevity research increasingly urgent — not just for individual patients, but for public health systems preparing for demographic shift.
"We need to raise awareness of the need to invest in this research, and the opportunities it holds to improve aging," Barak said. "We are hoping our research and similar efforts will improve the quality of life of older New Zealanders."
The study, led by Amy Hai Yan Chan and colleagues, adds to growing evidence that metformin may offer benefits extending well beyond blood sugar management. For the millions worldwide managing type 2 diabetes, the prospect of a medication that protects the heart, brain, and now shows promise against cancer represents something rare in medicine: a single tool addressing multiple dimensions of healthy aging.