When is metformin used for polycystic ovary syndrome (PCOS)?

Metformin helps the body respond to insulin and reduces the amount of sugar released by the liver. It is FDA-approved for type 2 diabetes, while its use for PCOS is off-label. A physician may consider it when PCOS occurs with insulin resistance, prediabetes, or other metabolic concerns.

Some people notice more regular periods while taking metformin. Results vary. It is not a cure for PCOS, a reliable birth control method, or a guaranteed weight-loss treatment. If ovulation becomes more regular, pregnancy may be possible even when past cycles were unpredictable. Tell your physician whether you want to avoid pregnancy or try to conceive.

Common side effects include diarrhea, nausea, gas, and stomach discomfort. Your prescriber may recommend taking it with food or adjusting the dose gradually. Follow your own prescription instructions rather than changing the dose yourself. Long-term use can lower vitamin B12 levels in some people.

Kidney function should be reviewed before treatment and monitored as needed. A rare but serious risk is lactic acidosis, especially in certain medical settings. Tell your care team about kidney disease, heavy alcohol use, severe illness, or any planned procedure involving contrast dye.