Fasting blood glucose 6.6mmol/L whether need to take metformin is related to specific conditions, if once in a while fasting blood glucose 6.6mmol/L, may not be caused by diabetes, may not need to take metformin; if fasting blood glucose 6.6mmol/L clearly diagnosed as diabetes or pre-diabetes, if necessary, you can follow the doctor’s instructions to take metformin treatment. The normal value of fasting blood glucose is between 3.9~6.1mmol/L, while fasting blood glucose 6.6mmol/L suggests that fasting blood glucose is elevated. Elevated fasting blood glucose can be caused by many factors, such as infection, stress, etc., or diabetes or pre-diabetes, which need to be diagnosed by a professional doctor to clarify the condition. If it is caused by infection, stress and other factors, you need to actively control the infection, relieve stress factors, and monitor blood glucose, if the blood glucose returns to normal, generally do not need to be treated with metformin. If it is diabetes or pre-diabetes, in the case of poor glycemic control by diet and exercise, it can be treated with metformin as prescribed by the doctor. Patients with fasting blood glucose of 6.6 mmol/L should consult a medical professional for consultation and treatment, and take the medication as prescribed by the doctor to avoid delaying the condition.