Metformin (Glucophage) price comparison 2026: cheapest pharmacy finder

Metformin is a biguanide oral antidiabetic that serves as the first-line treatment for type 2 diabetes worldwide. It works by reducing glucose production in the liver and improving insulin sensitivity in muscle tissue. Originally marketed as Glucophage by Bristol-Myers Squibb, metformin lost patent protection in 2002. It has since become the most prescribed diabetes medication in the United States, with tens of millions of prescriptions filled each year. Beyond diabetes, researchers are studying metformin for potential longevity and cancer-prevention benefits, though these uses remain off-label.

Generic metformin is a staple on $4 generic lists at Walmart, Kroger, Target, and other major pharmacy chains. Available in 500mg, 850mg, and 1000mg tablets, the immediate-release (IR) formulation is almost always cheaper than extended-release (ER). This price gap matters because many patients take the ER version to reduce gastrointestinal side effects like nausea and diarrhea. In 2020, the FDA requested recalls of several ER metformin products from manufacturers including Apotex, Amneal, and Teva due to elevated NDMA (a probable carcinogen) levels. Those contamination issues have since been resolved, and ER metformin is widely available again. For patients who need the liquid form, Riomet brand oral solution can cost 100 times more than generic tablets for the same active ingredient.

To minimize costs, ask your doctor whether immediate-release metformin taken with meals would work for you, since IR tablets are the cheapest option. A 90-day supply through Costco or Cost Plus Drugs often drops the per-month cost below

Sources and standards behind this page

Prescription prices in the United States are set through a documented chain of list prices, pharmacy benefit contracts and federal programs, and the sources below are the primary public records of how that chain works. They are linked so a reader can check a claim here without taking this page's word for it.

• FTC report on pharmacy benefit managers documents how the middlemen between an insurer and a pharmacy set what a drug costs at the counter.
• FDA Orange Book publishes the therapeutic-equivalence ratings that decide whether a cheaper generic may be substituted for a brand.
• FDA generic drug facts sets out what "generic equivalent" means and what a manufacturer must prove before selling one.
• Drugs@FDA is the federal database of approved drug products, which establishes whether a named product exists and in what form.
• DailyMed carries the current FDA labeling for every marketed drug product, including its approved strengths and forms.
• MedlinePlus drug information is the National Library of Medicine's consumer reference for what a given medication is and how it is used.
• CMS prescription drug coverage defines the rules a Medicare drug plan formulary must follow and how it may change during a plan year.
• Medicare.gov drug coverage (Part D) states what a Part D plan is required to offer a member and how its cost stages work.
• Medicare Plan Compare is the official tool for checking what a specific plan charges for a specific drug at a specific pharmacy.
• National Library of Medicine maintains the drug and health databases the sources above draw on.

This page describes how prescription pricing and discount programs work. It is not medical advice, and what a given person pays depends on their own plan, pharmacy and prescriber.