Metformin is a prescription medication used to treat type 2 diabetes. Metformin belongs to a group of drugs called biguanides, which work by helping your body respond better to the insulin it makes naturally, decreasing the amount of sugar your liver makes, and decreasing the amount of sugar your intestines absorb.
This medication comes in tablet, extended-release tablet, and liquid forms. It is taken up to 3 times daily, depending on which form you are taking. Swallow extended-release tablets whole.
Common side effects of metformin include diarrhea, nausea, and upset stomach.