Northwestern Study Finds Metformin Targets Intestinal Cells, Not Liver, in 1 Widely Used Diabetes Drug
Updated
Updated · SciTechDaily · May 21
Northwestern Study Finds Metformin Targets Intestinal Cells, Not Liver, in 1 Widely Used Diabetes Drug
3 articles · Updated · SciTechDaily · May 21
Mouse experiments showed metformin lost much of its glucose-lowering effect when intestinal cells were engineered to resist mitochondrial complex I blockade, pointing to the gut—not the liver—as its main site of action.
Researchers found the drug suppresses mitochondrial energy production in intestinal lining cells, forcing them to burn more glucose and pull excess sugar from the bloodstream.
The Nature Metabolism study also linked that gut mechanism to clinical clues seen in patients, including lower post-meal blood sugar, reduced citrulline and higher GDF15 levels tied to appetite suppression.
Berberine appeared to trigger the same intestinal pathway, but the authors said the supplement lacks metformin’s decades of clinical evidence and should not be treated as a substitute.
The findings could redirect diabetes drug development toward gut-targeted therapies and revise a long-held view that metformin works primarily by curbing liver glucose production.
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Metformin’s New Mechanism: The Gut, Not the Liver, as the Key to Glucose Control and the Future of Diabetes Therapy
Overview
A 2026 Northwestern University-led study has fundamentally changed our understanding of metformin, showing that its main glucose-lowering action happens in the gut, not the liver. The research reveals that metformin turns the gut into a 'sponge' or 'glucose sink,' forcing intestinal cells to absorb and metabolize more sugar from the bloodstream. This explains why people taking metformin often have lower blood sugar after meals. The shift in focus from the liver to the gut provides a clearer, more detailed insight into how metformin works, prompting a major re-evaluation of its mechanisms and opening new directions for diabetes treatment.