Short answer: The metformin label starts adults at 500 mg twice a day or 850 mg once a day, with meals. The dose goes up by 500 mg weekly or 850 mg every 2 weeks, based on blood sugar and tolerability, to at most 2,550 mg a day in divided doses. Children 10 and older start at 500 mg twice a day, up to 2,000 mg a day.
This is what the FDA label says. Follow your prescriber. Your prescriber may use a different dose or pace than the label's standard schedule.
What Metformin is approved for: Metformin is a biguanide approved, along with diet and exercise, to improve blood sugar control in adults and children 10 years and older with type 2 diabetes (section 1). The Patient Information says it is not for people with type 1 diabetes or for diabetic ketoacidosis.
Source
Metformin hydrochloride tablets, for oral use, prescribing information and Patient Information. Zydus Pharmaceuticals (USA). DailyMed, version published August 17, 2026. DailyMed setid c82a10fa-1e8e-46b6-890a-737de3f34ee1
Metformin is a tablet taken by mouth with meals; the Patient Information says this helps lessen upset stomach, and to swallow the tablets whole (section 2.1 and Patient Information).
It comes in 500 mg, 850 mg and 1,000 mg tablets (section 3). The Patient Information notes you may sometimes pass a soft mass in your stool that looks like the tablet.
Kidney function (eGFR) is checked before starting and periodically after (section 2.3).
The table below is the label's schedule, from the Dosage and Administration section. Numbers are copied exactly; the section is in brackets.
| Who | Starting dose | How it steps up | Maximum |
|---|---|---|---|
| Adults | 500 mg twice a day or 850 mg once a day, given with meals | In increments of 500 mg weekly or 850 mg every 2 weeks, based on glycemic control and tolerability | 2,550 mg per day, in divided doses; doses above 2,000 mg may be better tolerated 3 times a day with meals |
| Children 10 years and older | 500 mg twice a day, given with meals | In increments of 500 mg weekly, based on glycemic control and tolerability | 2,000 mg per day, in divided doses twice daily |
| Kidney function or situation | What the label says |
|---|---|
| eGFR below 30 mL/min/1.73 m2 | Contraindicated; discontinue if eGFR later falls below 30 |
| eGFR 30 to 45 mL/min/1.73 m2 | Starting metformin is not recommended |
| eGFR falls below 45 mL/min/1.73 m2 while taking it | Assess the benefit and risk of continuing |
| Iodinated contrast imaging with eGFR 30 to 60, liver disease, alcoholism, heart failure, or intra-arterial contrast | Discontinue at the time of or before the procedure; re-check eGFR 48 hours after and restart if kidney function is stable |
Adults start at 500 mg twice a day or 850 mg once a day with meals, rising by 500 mg weekly or 850 mg every 2 weeks to a maximum of 2,550 mg per day in divided doses. Doses above 2,000 mg may be better tolerated given 3 times a day with meals.
Children 10 years and older start at 500 mg twice a day with meals, rising by 500 mg weekly to a maximum of 2,000 mg per day, given in divided doses twice daily.
Kidney function is assessed before starting and periodically after, and at least once a year (section 5.1), more often in people at risk such as older adults.
Metformin is temporarily stopped while food and fluid intake is restricted for surgery or other procedures.
With insulin or an insulin secretagogue such as a sulfonylurea, a lower dose of those medicines may be needed to lower the risk of low blood sugar.
The Patient Information says: if you miss a dose, take your next dose as prescribed unless your healthcare provider tells you differently, and do not take an extra dose the next day. The prescribing information gives no separate missed-dose rule.
More on this: missed a dose of Metformin.
In Dose Track you set up Metformin as a protocol with the dose and schedule your prescriber gave you. A protocol can hold dose steps, each with its own dose and length in days or weeks, so a step-up plan like the one on the label can be entered once and the app moves to the next step on its own. Reminders follow the schedule, and every dose is logged with the date and time, so you can see which step you are on and when your last dose was. The app follows what you enter; it does not choose or change a dose.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.