Both Berberine and Metformin are simulators of AMPK activated protein kinase (kinase is an enzyme that catalyzes the transfer of phosphate groups from high energy eg in the ATP chemical reaction = the BODY'S ENERGY MOLECULE )
therfore Berberine and Metforman facilitates that process = EFFICENT ENERGY THAT BURNS  FATS & CARBS therefore those with metabolic syndrome (Sluggish metabolism) as we age and lack of balanced diet & exercise also hormonal down regulation = storage of visceral fats around the vital organs (heart and liver) .

I liken this to using SPARK PLUG CLEANER or FUEL INJECTOR ADDITIVE in your car to increase the performance & efficiency of the motor, in your bodies cells the cells motor is the body's furnace in every human cell called the MITOCHONDRION.
Graham Healy