If all metformin could do was reduce cancer incidence, it would still be worth prescribing widely. In the United States, the lifetime risk of being diagnosed with cancer is greater than 40 percent.24 But there’s a dividend beyond preventing cancer directly, a side effect of living longer that most people don’t consider: after age 90, your chances of dying of cancer drop considerably.25 Of course, people will still die of other conditions, but the tremendous pain and costs associated with cancer would be significantly mitigated.
