Berberine and its more biologically available derivative, dihydroberberine, inhibit mitochondrial respiratory complex I: a mechanism for the action of berberine to activate AMP-activated protein kinase and improve insulin action

Researchers tested berberine and dihydroberberine in lab-grown muscle cells and isolated mitochondria, the parts of cells that make energy. No people took part. Both substances slowed complex I, an important step in energy production, which lowered the cells’ energy supply. This activated AMPK, an energy-sensing switch, and increased the muscle cells’ uptake of sugar. Dihydroberberine produced stronger effects in these laboratory tests.

What this means for you: This suggests one possible explanation for berberine’s effects, but it does not prove that supplements improve health in people. Since the evidence came from cells and laboratory mitochondria, you can ignore this study when deciding whether to buy berberine.