Metformin is a prescription-only medication in Korea. This page is for educational purposes only and does not constitute medical advice. Never adjust, start, or stop diabetes medication without consulting your doctor. Regular blood glucose and kidney function monitoring is required during treatment.
Metformin is the most widely prescribed first-line medication for type 2 diabetes worldwide. It lowers blood glucose levels primarily by reducing the amount of sugar the liver releases into the bloodstream.
Metformin is a biguanide class antidiabetic medication and is universally recommended as the first-line pharmacological treatment for type 2 diabetes by major international guidelines including the American Diabetes Association (ADA) and the International Diabetes Federation. It works primarily by reducing hepatic (liver) glucose production, improving insulin sensitivity in peripheral tissues, and decreasing glucose absorption from the gut. Unlike some diabetes medications, metformin does not cause weight gain and has a low risk of causing hypoglycaemia (dangerously low blood sugar) when used alone.
In Korea, type 2 diabetes affects a significant proportion of the adult population. Metformin is available on prescription at community health centres and private pharmacies. It is available as immediate-release tablets, extended-release (XR) tablets, and in combination pills with other antidiabetic agents.
Long-term metformin use is associated with slightly reduced absorption of vitamin B12 — periodic monitoring of B12 levels is recommended. The most important safety precaution is that metformin must be temporarily withheld before procedures using iodinated contrast dye (e.g., CT scan with contrast) due to a rare risk of lactic acidosis in the context of acute kidney injury. Metformin is contraindicated in severe kidney impairment. Gastrointestinal side effects (nausea, diarrhoea) are the most common complaints, especially at initiation, and are reduced by taking the medication with food or switching to extended-release formulation.
This page is educational. Metformin is a prescription medicine in Korea — your doctor will prescribe and monitor it appropriately.
Key Points
- First-line oral medication for type 2 diabetes
- Reduces hepatic glucose output and improves insulin sensitivity
- Does not cause weight gain; low risk of hypoglycaemia alone
- Common side effect: gastrointestinal upset — take with food
- Must be paused before iodinated contrast procedures (CT scan with dye)
- Long-term use may reduce vitamin B12 — monitor B12 levels periodically
Causes & Risk Factors
- Type 2 diabetes mellitus — the primary indication
- Prediabetes in high-risk patients (some guidelines support use)
- PCOS (polycystic ovary syndrome) — used off-label to improve insulin sensitivity
- Prevention of diabetes in high-risk individuals (off-label, as directed by a doctor)
When to See a Doctor
- If you have been diagnosed with type 2 diabetes or prediabetes — for full assessment and treatment plan
- If you experience persistent nausea, abdominal pain, or diarrhoea on metformin
- Before any CT scan with contrast — inform your doctor you are taking metformin
- If your kidney function changes — dose adjustment or discontinuation may be needed
- For regular HbA1c and kidney function monitoring — typically every 3–6 months
- If you feel very unwell with weakness, unusual muscle pain, or breathing difficulty — rare but serious sign of lactic acidosis
For emergencies in Korea, call 119
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This content is published for educational purposes only. For accurate diagnosis and personalised treatment, consult a licensed KMA physician in Korea.
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Medical Disclaimer
This article is published by DoctorsInKorea.com for educational and informational purposes only. It does not replace a professional clinical evaluation by a licensed healthcare provider. For accurate medical diagnosis and personalised treatment paths, please book an appointment with a licensed KMA physician. For immediate life-threatening medical emergencies in Korea, please call 119.
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Last reviewed: May 29, 2026