What Is Metformin? Uses, Dosage, and What You Need to Know in 2026

Metformin is an oral medication used to lower blood sugar levels in people with type 2 diabetes. It is the most widely prescribed diabetes drug in the United States and around the world, with over 90 million prescriptions written annually in the U.S. alone. If you or someone you care about has been prescribed Metformin, here's everything you need to know — from what it does, to how to take it, to what it costs in 2026.

What is Metformin?

Metformin belongs to a class of medications called biguanides. It was first approved by the FDA in 1995 and has been a cornerstone of type 2 diabetes treatment ever since. It is available as a generic medication, making it one of the most affordable diabetes treatments on the market.

Here are the key facts:

• Generic name: Metformin hydrochloride
• Brand names: Glucophage, Glucophage XR, Fortamet, Glumetza, Riomet
• Drug class: Biguanide (antihyperglycemic)
• Controlled substance: No — Metformin is not a controlled substance and does not require special prescribing restrictions
• FDA approval: 1995 (immediate-release), 2000 (extended-release)
• Manufacturers: Multiple generic manufacturers; original brand (Glucophage) by Bristol-Myers Squibb

What is Metformin used for?

Metformin is primarily prescribed to manage type 2 diabetes, but it has several important uses:

FDA-approved uses

• Type 2 diabetes mellitus — Metformin is considered the first-line medication for type 2 diabetes by the American Diabetes Association (ADA). It helps lower blood sugar by reducing the amount of glucose your liver produces and improving your body's sensitivity to insulin.

Common off-label uses

• Prediabetes — Often prescribed to help prevent the progression from prediabetes to type 2 diabetes, especially in patients with a BMI over 35 or those under 60
• Polycystic ovary syndrome (PCOS) — Helps regulate menstrual cycles and improve insulin resistance in women with PCOS
• Gestational diabetes — Sometimes used as an alternative to insulin during pregnancy, though this should only be done under close medical supervision
• Weight management — While not FDA-approved for weight loss, Metformin is sometimes prescribed off-label because it can lead to modest weight reduction in some patients

How is Metformin taken?

Metformin comes in several forms to fit different needs:

Available dosage forms

• Immediate-release tablets: 500 mg, 850 mg, 1,000 mg — taken 2-3 times daily with meals
• Extended-release tablets (Metformin ER): 500 mg, 750 mg, 1,000 mg — taken once daily with the evening meal
• Oral solution (Riomet): 500 mg/5 mL — for patients who have difficulty swallowing tablets

Typical dosing

Most adults start on 500 mg once or twice daily with meals. Your doctor will gradually increase the dose over several weeks to minimize side effects (especially GI symptoms). The maximum recommended dose is 2,550 mg per day for immediate-release and 2,000 mg per day for extended-release.

Important: Always take Metformin with food to reduce stomach upset. Swallow extended-release tablets whole — do not crush, chew, or split them.

Who should not take Metformin?

While Metformin is safe for most people, there are some important contraindications:

• Severe kidney disease — Metformin is cleared by the kidneys. If your eGFR is below 30 mL/min, Metformin should not be used. If your eGFR is between 30-45, your doctor may use a reduced dose with close monitoring.
• Metabolic acidosis or diabetic ketoacidosis (DKA) — Metformin carries a rare but serious risk of lactic acidosis
• Severe liver disease — Impaired liver function increases the risk of lactic acidosis
• Before certain medical procedures — Metformin should be temporarily stopped before surgeries or imaging procedures that use iodinated contrast dye, as these can affect kidney function
• Heavy alcohol use — Excessive alcohol consumption increases the risk of lactic acidosis and hypoglycemia

Always tell your doctor about all your medical conditions and medications before starting Metformin.

How much does Metformin cost?

Metformin is one of the most affordable prescription medications available. Because it has been generic for decades, prices are very low compared to newer diabetes drugs:

• Without insurance: $4–$20 for a 30-day supply of immediate-release tablets (many pharmacies include it on their $4 generic list)
• Extended-release: $10–$40 for a 30-day supply without insurance
• With insurance: Typically $0–$10 copay. Metformin is on virtually every insurance formulary as a preferred generic.

For more ways to save, check out our complete guide to saving money on Metformin.

Final thoughts

Metformin has been a trusted diabetes treatment for over 30 years, and for good reason. It's effective, affordable, well-studied, and safe for the vast majority of patients. Whether you're newly diagnosed with type 2 diabetes or have been managing it for years, Metformin is likely a key part of your treatment plan.

Here's what to remember:

1. Metformin is the first-line treatment for type 2 diabetes and works by reducing liver glucose production and improving insulin sensitivity
2. It comes in immediate-release and extended-release forms — always take it with food
3. It's one of the most affordable medications available, often $4 or less per month
4. Tell your doctor about any kidney issues, liver problems, or upcoming medical procedures before starting Metformin

Need help finding Metformin at a pharmacy near you? Medfinder can help you locate pharmacies with your medication in stock — no phone calls required.

More about Metformin

• How Does Metformin Work? Mechanism of Action Explained
• Metformin Side Effects: What to Expect and When to Call Your Doctor
• Metformin Drug Interactions: What to Avoid
• Alternatives to Metformin If You Can't Fill Your Prescription
• How to Find Metformin in Stock Near You (Tools + Tips)