Why Longevity Researchers Are Interested in Metformin
Metformin is a cheap, widely prescribed diabetes drug with an extraordinary safety record spanning 60+ years. In observational studies, diabetic patients on metformin outlive non-diabetic people not on it — an astonishing finding that suggested it might be doing something beyond blood sugar control. The TAME trial (Targeting Aging with Metformin) is testing this directly in a major US clinical study.
The Mechanisms
Metformin activates AMPK (an energy sensor that mimics effects of caloric restriction), reduces mTOR signalling, lowers systemic inflammation, and may have direct effects on the gut microbiome composition. It reduces fasting glucose and insulin without the hypoglycaemia risk of other diabetes drugs.
Current Evidence for Non-Diabetics
The TAME trial results are expected 2025–2027. Until then, the evidence is observational and mechanistic — not direct proof. Some longevity physicians prescribe it preventively at low dose (500mg–1g daily); others argue we should wait for trial data. Exercise caution: metformin may blunt some of the metabolic adaptations to vigorous exercise, which is concerning given exercise’s own powerful longevity benefits.
Access in the UK
Metformin requires a prescription in the UK. Some private GPs will prescribe it off-label for longevity purposes; most won’t without diabetes or pre-diabetes indicators. It costs pennies per tablet on the NHS. Private prescription: approximately £20–40/month through private GP services.
⚕️ Do not self-medicate with metformin. It requires medical supervision and regular monitoring of kidney function and B12 levels.