Berberine

Activates AMPK (AMP-activated protein kinase) — the same metabolic switch as metformin and exercise
Multiple RCTs show comparable glucose-lowering effect to metformin at 1500mg/day
Reduces fasting glucose, post-meal glucose spike, HbA1c, and LDL cholesterol
Take with meals — this is mechanistically important; it blunts the glucose response to that specific meal
Not a replacement for diet change — most effective when combined with reduced refined carbs

Personal observations, timing, dose adjustments — add notes here as experience builds.