What Is Janumet?

Janumet is a prescription medication that combines two diabetes drugs — Sitagliptin and Metformin Hydrochloride — into a single tablet. It's manufactured by Merck & Co. and is used along with diet and exercise to improve blood sugar control in adults with type 2 diabetes.

Think of it as two proven medications in one pill. Instead of taking Sitagliptin (sold separately as Januvia) and Metformin as two separate tablets, Janumet puts them together for convenience and potentially better adherence to your treatment plan.

What Does Janumet Treat?

Janumet is FDA-approved for one primary use:

• Type 2 diabetes mellitus — as an add-on to diet and exercise to improve blood sugar (glycemic) control in adults

It is not approved for:

• Type 1 diabetes
• Diabetic ketoacidosis (DKA)
• Use in children under 18

Your doctor may prescribe Janumet if Metformin alone isn't controlling your blood sugar well enough, or if you're already taking both Sitagliptin and Metformin separately and want to simplify your regimen.

How Does Janumet Work?

Janumet attacks high blood sugar from two different angles:

1. Sitagliptin (DPP-4 inhibitor) — Works by increasing levels of natural hormones called incretins (GLP-1 and GIP). These hormones tell your pancreas to make more insulin when your blood sugar is high and tell your liver to stop making excess sugar. Importantly, they only work when blood sugar is elevated, which reduces the risk of low blood sugar.
2. Metformin (biguanide) — Reduces the amount of sugar your liver produces, decreases the amount of sugar absorbed from food, and helps your body respond better to its own insulin.

For a deeper dive into the science, read our article on how Janumet works.

Janumet Dosage Forms and Strengths

Janumet comes in two formulations:

Janumet (Immediate-Release)

Taken twice daily with meals:

• 50mg/500mg — 50mg Sitagliptin + 500mg Metformin
• 50mg/850mg — 50mg Sitagliptin + 850mg Metformin
• 50mg/1000mg — 50mg Sitagliptin + 1000mg Metformin

Janumet XR (Extended-Release)

Taken once daily with the evening meal:

• 50mg/500mg — 50mg Sitagliptin + 500mg Metformin ER
• 50mg/1000mg — 50mg Sitagliptin + 1000mg Metformin ER
• 100mg/1000mg — 100mg Sitagliptin + 1000mg Metformin ER

The maximum daily dose is 100mg of Sitagliptin and 2000mg of Metformin.

How to Take Janumet

Proper dosing makes a real difference in both effectiveness and side effects:

• Janumet (immediate-release): Take one tablet twice daily with meals. Take one with breakfast and one with dinner.
• Janumet XR (extended-release): Take once daily with your evening meal.
• Swallow tablets whole — do not crush, cut, or chew, especially Janumet XR
• Always take with food — this reduces stomach side effects and helps the medication work properly
• Start low, go slow — your doctor should start you at a lower Metformin dose and increase gradually to minimize digestive side effects

If you miss a dose, take it as soon as you remember (with food). If it's almost time for your next dose, skip the missed one. Never double up.

Who Should Not Take Janumet

Janumet is not right for everyone. You should not take it if you have:

• Severe kidney disease — eGFR below 30 mL/min/1.73m²
• A known allergy to Sitagliptin, Metformin, or any DPP-4 inhibitor
• Metabolic acidosis — including diabetic ketoacidosis
• A history of serious allergic reaction to any DPP-4 inhibitor (swelling, hives, difficulty breathing)

You should use Janumet with caution if you:

• Are over 65 years old (increased risk of lactic acidosis)
• Have moderate kidney impairment
• Drink alcohol regularly
• Have liver problems
• Are scheduled for surgery or a procedure using iodinated contrast dye

Janumet Side Effects

The most common side effects include:

• Diarrhea
• Nausea
• Stomach pain and bloating
• Headache
• Upper respiratory symptoms (stuffy nose, sore throat)
• Metallic taste

These usually improve within 2-4 weeks. More serious but rare side effects include lactic acidosis (boxed warning), pancreatitis, severe allergic reactions, and severe joint pain.

For the complete breakdown, read our detailed guide on Janumet side effects.

Drug Interactions

Janumet interacts with several medications and substances:

• Insulin and sulfonylureas — may cause low blood sugar
• Topiramate, Zonisamide — increase lactic acidosis risk
• Iodinated contrast dye — must temporarily stop Janumet
• Alcohol — increases risk of lactic acidosis
• Cimetidine — may increase Metformin levels

Always tell your doctor about all medications, supplements, and over-the-counter drugs you take. See our complete guide on Janumet drug interactions.

How Much Does Janumet Cost?

Janumet is a brand-name medication with no generic currently available. Here's what pricing looks like in 2026:

• Without insurance: $600-$750 for a 30-day supply (60 tablets)
• With insurance: Typically $30-$90 per month copay (varies by plan)
• Merck savings card: As little as $5 per prescription for commercially insured patients
• Patient assistance: Free through Merck Helps for eligible uninsured/underinsured patients

The Sitagliptin patent expires in November 2026, so a generic version of Janumet may become available in late 2026 or 2027 — which could dramatically lower costs.

For all the ways to save, read our guide on how to save money on Janumet.

Janumet vs. Taking Sitagliptin and Metformin Separately

If you're already taking Sitagliptin (Januvia) and Metformin as separate pills, Janumet combines them into one. Benefits of the combination include:

• Fewer pills to take — simplifies your daily routine
• Better adherence — studies show patients are more likely to stick with treatment when taking fewer pills
• Same effectiveness — you're getting the same active ingredients

The downside: Janumet is brand-name only, while generic Metformin is very inexpensive. If cost is a major factor, taking generic Metformin + brand-name Januvia separately might be worth discussing with your doctor.

Alternatives to Janumet

If Janumet isn't the right fit, similar combination medications include:

• Jentadueto (Linagliptin/Metformin) — doesn't need kidney dose adjustment
• Kombiglyze XR (Saxagliptin/Metformin ER) — once-daily dosing
• Kazano (Alogliptin/Metformin) — twice daily, similar to Janumet

For more options, check out our guide on alternatives to Janumet.

Key Takeaways

• Janumet combines Sitagliptin + Metformin to treat type 2 diabetes
• It comes in immediate-release (twice daily) and extended-release (once daily) forms
• Always take with food to reduce side effects
• Regular kidney function monitoring is required
• No generic available yet — but one may arrive in late 2026
• Merck's savings card can bring the cost to as low as $5/month

Ready to find Janumet at a pharmacy near you? Search on MedFinder or learn how to check pharmacy stock.