About Metformin
Medically reviewed by Dr Khizer Hussain Junaidy, MD Pharmacology, Diabetologist & Bariatric Physician, on 23 Oct 2026.
What it is for
Lowers blood sugar in type 2 diabetes. It reduces the sugar made by the liver and helps the body use insulin better. It is also used in prediabetes and in PCOS when the doctor advises.
How to take it
Take it with food or just after a meal, to reduce stomach upset. Extended-release (SR, XR) tablets are swallowed whole, not crushed or chewed. The doctor usually starts with a low dose and increases it slowly.
Common side effects
- Loose stools, gas, nausea or a metallic taste in the first few weeks. These usually settle.
- Low vitamin B12 after long use, which can cause tingling in the feet.
Call your doctor if
- Severe vomiting, diarrhoea or you cannot eat or drink.
- Unusual muscle pain, fast breathing, or feeling very weak and cold.
- Before a CT scan with contrast dye or a surgery. The doctor may pause it for a short time.
Take care
Avoid heavy alcohol. Tell the doctor about any kidney or liver disease.
From our clinic: On its own, metformin rarely causes low sugar. Ask for a vitamin B12 test once a year if you have taken it for many years.