Berberine
500 mg, two to three times daily. Functions as a weaker pharmacologic glucose-lowering agent.
What it does
Real glucose-lowering effects in human trials — closer to a pharmacologic agent than a typical supplement, with a mechanism that overlaps metformin. The unprescribed-but-active option for metabolic dysfunction.
Activates AMPK, the cellular energy sensor behind much of metformin's effect, reducing hepatic glucose output and improving insulin sensitivity.
What the evidence shows
Overall evidence strength: Moderate certainty
Who it's for, who should skip
Metabolic dysfunction in people not on prescription glucose-lowering therapy. If a prescription is appropriate, that is usually the better path. Watch CYP3A4 drug interactions.
Running it
- Form
- oral
- Dose
- 500 mg · 2–3x/day · with meals
Measuring it
Retest HbA1c — monitor glucose if combining with other glucose-lowering agents.
Safety
- GI effects (nausea, cramping, diarrhea), especially at higher doses
- CYP3A4 drug interactions; inconsistent product quality control
Stacking & alternatives
Access & cost
Available over the counter. Look for: third-party tested berberine.
Last reviewed 27 August 2026.