The quest to defy aging has fueled myths, diets, and billion-dollar industries, but the answer to preserving youth might lie in a humble, $4-a-month pill already sitting in medicine cabinets worldwide.
A startling study from China has reignited this possibility, showing that metformin, a drug used for over 60 years to treat type 2 diabetes, reversed biological aging in monkey brains by the equivalent of 18 human years. Scientists are now racing to see if this diabetes staple could help humans stay sharper, longer.
In a meticulously designed trial published in the journal Cell, researchers at the Chinese Academy of Sciences studied 12 elderly male macaque monkeys, giving them daily doses of metformin for 40 months, roughly equivalent to 13 years of human use. For comparison, 16 elderly and 18 younger monkeys served as untreated controls. Over the study period, scientists tracked the animals’ organ health, cognitive abilities, and cellular aging through tissue biopsies, brain scans, and memory tests.
The results were striking. By analyzing genetic and cellular markers, the team calculated the biological age of the metformin-treated monkeys’ organs. Their livers, lungs, kidneys, and skin aged slower, but the most dramatic reversal occurred in their prefrontal cortex, the brain region responsible for complex decision-making and memory. These monkeys’ brains became biologically six years younger than their untreated peers. Translated to human terms, that’s akin to an 80-year-old’s brain functioning like a 62-year-old’s. Even more compelling, the treated monkeys outperformed controls in cognitive tasks, suggesting sharper mental acuity.
Metformin’s secret lies in its ability to activate NRF2, a protein that acts like a cellular bodyguard. NRF2 shields DNA from damage caused by inflammation, oxidative stress, and toxins, all key drivers of aging. By boosting NRF2, metformin appears to slow the accumulation of cellular wear and tear, effectively turning back the clock on organ function. “This drug doesn’t just slow aging—it actively rejuvenates tissues,” explains lead researcher Guang-Hui Liu, a professor at the Chinese Academy of Sciences.
But the implications go beyond monkeys. Previous studies have hinted at metformin’s anti-aging potential in humans. Diabetics on the drug often live longer than non-diabetics, and research suggests it may reduce cancer risk, combat obesity, and even protect against dementia. Still, the idea of repurposing it as a broad-spectrum anti-aging therapy has long been controversial until now.
Buoyed by their primate findings, Liu’s team has partnered with German pharmaceutical giant Merck to launch a clinical trial involving 120 human participants. The goal is to see if metformin can replicate its brain-rejuvenating effects in people. Meanwhile, a separate U.S.-initiated project, Targeting Aging with Metformin (TAME), aims to recruit 3,000 adults aged 65 to 75 for a six-year study. Backed by $50 million in funding, TAME will examine whether metformin can delay age-related diseases like heart failure, cancer, and cognitive decline.
“This isn’t about living forever,” says Dr. Nir Barzilai, a gerontologist leading the TAME trial. “It’s about extending healthspan, the years we live free of chronic disease. If metformin works, it could revolutionize how we approach aging.”
Not everyone is convinced. Critics point to the monkey study’s small size (just 12 treated animals) and lack of female subjects. Aging experts also caution that translating animal results to humans is notoriously tricky. “Monkeys aren’t people, and aging is a complex process influenced by genetics, lifestyle, and environment,” says Dr. Matt Kaeberlein, a biogerontologist unaffiliated with the study. “But the mechanistic evidence here is too exciting to ignore.”
Another hurdle is proving metformin’s effects aren’t just masking aging symptoms but truly reversing biological decline. To address this, future trials will track biomarkers like DNA methylation, a key aging clock, and inflammation levels.
Aging is the single greatest risk factor for diseases like Alzheimer’s, heart disease, and cancer. Yet most medicines target individual conditions, not the root cause. Metformin’s appeal lies in its simplicity: it’s safe, affordable, and already prescribed to 150 million people globally. If proven effective, it could become the first FDA-approved drug to treat aging itself, a paradigm shift in medicine.
For now, scientists urge caution. “No one should start taking metformin off-label for anti-aging,” warns Liu. “But if the human trials confirm what we’ve seen in monkeys, this could be a game-changer.”
Beyond metformin, this research underscores a growing truth: Aging may not be inevitable. From senolytics (drugs that clear zombie cells) to gene therapies, the field of longevity science is booming. Metformin’s story, a repurposed drug with unexpected benefits, highlights how existing tools might hold untapped potential.
As the human trials unfold, one question looms: Could a pill that costs pennies a day help us retain our mental edge into our 80s and 90s? For millions grappling with cognitive decline, the answer can’t come soon enough. Until then, the humble diabetes drug has given us something rare in science - a reason to hope that growing older might not mean slowing down.