An Unexpected Clue To How Metformin, The World’s Top Diabetes Drug, Works

Metformin is an unassuming hero of modern medicine. For more than sixty years, this humble pill has been a mainstay of diabetes care, helping millions of people manage their blood sugar. It lowers blood sugar, improves cholesterol, modestly reduces weight, and is so safe it’s prescribed to millions worldwide. And yet, for decades, scientists haven’t fully understood how it works.

The standard explanation has long been that metformin works in the liver, reducing how much sugar it sends…