Both lower blood sugar through different mechanisms.
Berberine is a potent glucose-lowering compound. Cinnamon improves insulin sensitivity.
Monitor blood sugar. Lower risk than berberine + medication, but still worth tracking.
Known drug category interactions for these supplements. Especially relevant if you take prescription medications.
Berberine lowers blood sugar through similar mechanisms as metformin, and combining them may cause hypoglycemia.
Do not combine without medical supervision. If your doctor approves, start berberine at a low dose and monitor blood sugar closely.