Can the medication metformin lower blood sugar too much?

Usually no: Metformin is an excellent diabetes medication because it lowers your blood sugar by making you more sensitive to your own insulin, but it will not allow your glucose to go low. Other diabetes medications (glyburide or other sulfonylureas; insulin) can give you hypoglycemia. If your sugars are "low", maybe you don't need the metformin. Has something changed from when you were started (eg wt loss)?