Metformin and cancer: why active surveillance replaces certainty

Metformin, the flagship drug of the biohacker longevity movement, does not prevent prostate cancer as hoped—and that failure is precisely the data that should reshape how we think about preventive interventions in precision medicine. Peter Attia examines why clinical trials show sustained inefficacy across multiple cancer types, challenging the popular narrative surrounding this cheap, accessible antidiabetic. Yet not all populations respond identically: exceptional cases suggest the problem is not the drug itself, but our inability to identify who will benefit and who won't. For readers invested in longevity, this means abandoning the one-size-fits-all protocol and adopting active surveillance based on specific biomarkers, genomics, and individual risk profiles. The lesson is not to reject metformin, but to demand diagnostic stratification before any systemic intervention, transforming hope into applied science.