A new American study indicates that prolonged use of the diabetes medication metformin may significantly lower the risk of developing dementia later in life, though researchers emphasise further research is necessary.
A common medicine used to treat type 2 diabetes may be linked to a substantially lower risk of dementia later in life, according to a new American study reported by Science. The findings add to a growing body of research suggesting that metformin may have benefits beyond blood-sugar control, although experts say the evidence is still not strong enough to treat the drug as a proven way to prevent cognitive decline.
The analysis drew on long-term follow-up data from the Diabetes Prevention Program and its Outcomes Study, a research effort that began in the late 1990s and has tracked people at high risk of developing type 2 diabetes for years. Researchers examined 1,483 participants with a mean age of 74, all of whom had originally been assigned to metformin, placebo or an intensive lifestyle programme aimed at changing diet and exercise habits. Those first assigned to metformin had, on average, 15.5 years of exposure to the drug during follow-up.
When cognitive function was assessed in 2022 to 2024, long-term metformin use was associated with a 60% lower likelihood of dementia compared with placebo, and a 62% lower likelihood compared with the intensive lifestyle group, according to the report. Metformin users also performed slightly better on memory tests over time. But the researchers urged caution, saying the results should be interpreted carefully and that more data are needed before any firm conclusion can be drawn.
The new findings fit with earlier studies pointing in the same direction. Research published in Alzheimer’s & Dementia in 2023 found lower dementia risk among people with type 2 diabetes who used metformin, while a separate UK database study in the same journal also reported a reduced risk among people starting the drug. Other observational work, including studies in Diabetes Care and The Lancet Healthy Longevity, has likewise suggested a possible protective effect, though the authors of those papers also emphasised that this does not prove cause and effect.
For now, metformin remains primarily a treatment for type 2 diabetes, and it should only be used under medical advice. The latest study offers a promising signal that long-term use may also support brain health, but researchers say a definitive answer will require further trials and longer follow-up.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
