Berberine

Berberine's primary mechanism is activation of AMPK (AMP-activated protein kinase) — the cellular energy sensor that mediates many of metformin's beneficial effects including suppression of hepatic glucose production, enhancement of insulin sensitivity, and mTOR inhibition. Berberine also inhibits mitochondrial complex I, directly increasing AMP:ATP ratios that trigger AMPK. Additionally berberine modulates the gut microbiome — increasing populations of beneficial bacteria while reducing pathogenic species — and these microbiome changes contribute significantly to its metabolic effects. Berberine inhibits the enzyme PCSK9, which plays a key role in LDL receptor degradation, contributing to its LDL-lowering effects. It also has direct anti-inflammatory effects through NF-κB inhibition and antioxidant properties.