Short answer: Janumet is taken by mouth twice daily with meals. Without current metformin, the label starts at 50 mg sitagliptin and 500 mg metformin twice daily, raised gradually to reduce stomach side effects. The maximum is 100 mg sitagliptin and 2,000 mg metformin a day. It is not used with an eGFR below 30. The Medication Guide says a missed dose is taken when remembered unless the next dose is due.
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 Janumet is approved for: Janumet combines sitagliptin, a DPP-4 inhibitor, with metformin, a biguanide. It is approved, along with diet and exercise, to improve blood sugar control in adults with type 2 diabetes (section 1). It should not be used in type 1 diabetes, and it has not been studied in people who have had pancreatitis.
Source
JANUMET (sitagliptin and metformin hydrochloride) tablets, for oral use, prescribing information and Medication Guide. Merck Sharp & Dohme. DailyMed, version published August 27, 2026. DailyMed setid d19c7ed0-ad5c-426e-b2df-722508f97d67
Janumet is a tablet taken by mouth twice daily with meals. Tablets are not split or divided (section 2.1).
It comes as sitagliptin 50 mg with metformin 500 mg, and sitagliptin 50 mg with metformin 1,000 mg (section 3).
The dose is set by the current regimen, how well it works and how well it is tolerated (section 2.1).
The table below is the label's schedule, from the Dosage and Administration section. Numbers are copied exactly; the section is in brackets.
| Current treatment | Janumet starting dose |
|---|---|
| Not currently treated with metformin | 50 mg sitagliptin and 500 mg metformin HCl twice daily, with gradual dose escalation |
| Already treated with metformin | Sitagliptin 50 mg twice daily (100 mg total daily dose) and the dose of metformin already being taken |
| Taking metformin HCl 850 mg twice daily | 50 mg sitagliptin and 1000 mg metformin HCl twice daily |
| Maximum recommended daily dose | 100 mg of sitagliptin and 2000 mg of metformin HCl |
Kidney function is assessed before starting and periodically after. Janumet is contraindicated with an eGFR below 30 mL/min/1.73 m2, and not recommended at 30 to under 45, because those people need a lower sitagliptin dose than the fixed combination has.
Janumet is stopped at the time of, or before, an iodinated contrast imaging procedure in people with an eGFR of 30 to 60, a history of liver disease, alcoholism or heart failure, or intra-arterial contrast. eGFR is rechecked 48 hours after, and Janumet restarted if kidney function is stable.
Janumet is stopped for a time while food and fluid intake is restricted for surgery or other procedures.
With insulin or a sulfonylurea, a lower dose of those medicines may be needed to reduce the risk of low blood sugar.
Tablets are stored at 20 to 25 C (68 to 77 F), with excursions from 15 to 30 C allowed.
The prescribing information has no missed-dose section. The Medication Guide says: if you miss a dose, take it as soon as you remember. If you do not remember until it is time for your next dose, skip the missed dose and go back to your regular schedule. Do not take 2 doses of Janumet at the same time.
More on this: missed a dose of Janumet.
For people already on metformin, the starting Janumet dose gives sitagliptin 50 mg twice daily plus the metformin dose already being taken. Someone on metformin 850 mg twice daily starts at 50 mg/1,000 mg twice daily.
In Dose Track you set up Janumet 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.