Berberine

Berberine is an isoquinoline alkaloid found in multiple plant genera, including Berberis, Hydrastis canadensis (goldenseal), and Coptis chinensis. It is sold as a dietary supplement in most jurisdictions and is not an approved drug in the EU or US. Berberine inhibits mitochondrial complex I, raising the AMP:ATP ratio and thereby activating AMPK downstream; small trials show modest reductions in fasting glucose, HbA1c, LDL cholesterol, and triglycerides in metabolic syndrome and type 2 diabetes. Marketed informally as natural metformin, evidence quality is limited, product purity varies, and CYP3A4-mediated drug interactions warrant caution. Longevity use is investigational.