Metformin: Activation of 5' AMP-activated protein kinase

Researchers tested metformin in laboratory-grown cells, not people. They measured AMPK, a protein that helps cells sense and manage their energy supply. Metformin increased signs that AMPK was active, apparently by making cells respond to lower energy levels. Because this was a cell study, it does not show that metformin extends human life or improves health in people.

What this means for you: This is a possible explanation for how metformin works, but it is not a reason to take it for longevity. You can ignore this one when deciding what to buy or use.