Metformin’s primary effect occurs in the gut, not the bloodstream as previously believed, new research shows.

The study published in Diabetes Care outlines results from phase 1 and phase 2 studies involving the investigational drug metformin delayed release (Metformin DR), which is designed to target the lower bowel and limit absorption into the blood.

“Our clinical trials show that metformin works largely in the lower intestine, reversing half a century of conventional thinking,” said lead author John Buse director of the diabetes care centre at University of North Carolina.

“These findings create an opportunity to develop a new metformin treatment option for the 40 percent of patients that currently can’t take this first-line drug of choice.”

“One of the top reasons metformin isn’t used for all people with type 2 diabetes is that patients with impaired kidneys accumulate too much drug in the blood, and this can result in life-threatening lactic acidosis. These studies provide evidence that delivering Metformin DR to the lower bowel significantly reduces the amount of metformin in the blood, while maintaining its glucose-lowering effect,” he added.