Metformin’s anti-ageing promise remains unproven as human trials gather pace

The diabetes drug affects pathways linked to ageing, but researchers say observational findings are not yet proof that it can extend healthspan or slow biological decline.

Metformin, the low-cost diabetes drug taken by millions of people with type 2 diabetes, is once again drawing attention for a possible role beyond blood sugar control. But the evidence for it as an anti-ageing treatment remains suggestive rather than conclusive, and the strongest human data so far still stop short of showing that it can genuinely slow biological ageing. A 2017 systematic review and meta-analysis indexed in PubMed found lower all-cause mortality among metformin users, along with fewer cancers and cardiovascular events, but that did not amount to proof that the drug reverses or delays ageing itself.

The scientific interest comes from the way metformin appears to act on several pathways linked to ageing, including metabolism, inflammation and mitochondrial function. Research summaries indexed in PubMed and more recent work on epigenetic ageing suggest a pattern worth studying, with some findings pointing to lower biological-age markers in people prescribed the drug. Even so, researchers caution that these results do not establish metformin as an anti-ageing therapy, because observational signals can be influenced by the health profile of the people taking it and by differences in treatment choices.

That is why large clinical trials matter. The TAME, or Targeting Aging with Metformin, study was designed to test whether the drug could delay multiple age-related diseases in older adults without diabetes, and the ANTHEM Aging Study was set up to examine whether metformin can target ageing and extend healthspan in humans. More recently, a randomised placebo-controlled trial reported in medRxiv looked at frailty progression in older adults with glucose intolerance and also tracked DNA methylation-based biological ageing clocks, showing how the question is now being tested with more direct measures of age-related decline.

There are also reasons for caution. A PubMed study from 2000 highlighted the need for close monitoring when metformin is used in older patients, particularly because of the risk of lactic acidosis in vulnerable people. More recent commentary has underscored that the anti-ageing case for metformin remains unresolved, with scientists still debating whether the drug’s apparent benefits reflect true effects on ageing biology or simply better control of underlying disease.

For people with diabetes, the practical message is more straightforward. Metformin remains an established treatment for managing blood sugar, but it should not be viewed as a shortcut to youth or longevity. The broader advice on diabetes care still applies: cut added sugar, reduce refined starches, choose whole grains and vegetables, include nuts and seeds, stay active after meals and build regular exercise into daily life.