Metformin as a potential longevity medication: where do we stand?

Humans have sought interventions for lifespan extension for millennia, though over the last century, this quest has taken on a more formal, scientific approach. Since the early 20th century, such research has led to the identification of several potential “longevity molecules,”¹ and in recent years, metformin has emerged as one of the most discussed candidates for this role, generating both excitement and skepticism within the scientific community.

While many are familiar with metformin as a common medication for the treatment of type 2 diabetes, the narrative around potential anti-aging properties of this drug began to take shape in the early 2000s with the discovery of life-extension effects in certain animal models. Subsequent observational data from humans fueled further excitement, but as conflicting evidence emerged in more recent years, interest in the possible role of metformin in human life extension began to lose steam. Yet in the late summer of 2024, a new study showing positive effects on aging markers in monkeys caught the attention of scientists and the popular press alike, and suddenly, metformin appeared to be back at the forefront of optimism over longevity drugs.

So where does this leave us? How does the strength of evidence in favor of metformin as a longevity drug compare to the strength of evidence against it? What are the implications for the use of this drug in promoting healthspan versus lifespan? And what questions remain to be answered?