What pharmacies paid for metformin, 2013 to 2026

In October 2026, retail pharmacies paid an average of 1.47 cents for a generic 500 mg metformin tablet, according to the federal government's NADAC survey files³. At that rate, 730 tablets, two a day for a year, cost a pharmacy $10.71 before anyone is paid to fill the prescription.

In November 2013, when the National Average Drug Acquisition Cost series¹ begins, the same tablet cost 1.80 cents, or $13.10 for 730. In between, the monthly figure never went higher than 2.06 cents (February 2014) or lower than 1.25 cents (July 2024). For 13 years, one of the most prescribed drugs in the country has cost pharmacies about a cent and a half a tablet.

Metformin was the second-cheapest drug per unit in GxRadar's 47-drug price basket in January 2014 and the third-cheapest in October 2026. GxRadar analyzed CMS NADAC files through October 2026, FDA approval and recall records, and Medicare prescription data to show how a price that low has held, and what the price of the tablet leaves out of the cost of a prescription.

Thirteen years at about a cent and a half

Figures are GxRadar's monthly median of the weekly NADAC per-tablet rate for generic-classified, immediate-release metformin 500 mg tablets, for the first month of the series and October of each year after. The last column multiplies the rate by 730. That is an illustration only. Actual prescriptions vary in strength, tablet count and release type, and the prescriber sets the dose. The full monthly series is on our metformin page.

The total drop since 2013 is 18 percent. For comparison, the median drug among the 43 in our basket with data for both January 2014 and October 2026 fell 43 percent over that span, and some fell much further. Drugs that were still relatively expensive in 2014 had more room to fall. Metformin had very little.

The 2024 swings

In 2024 the series went through its most turbulent stretch. The tablet started that year at 1.67 cents, dropped to 1.26 cents in May, bounced to 1.39 cents in June, hit the series low of 1.25 cents in July and was back at 1.49 cents by September, according to the 2024 NADAC files². It fell again to 1.26 cents in December.

Movements like these were common across generics that year, as our account of the 2024 NADAC swings shows, and CMS responded. Its December 2024 methodology⁴ describes "a temporary, short-term measure to address rate volatility occurring as a result of fluctuations in survey participation." Starting with the December 2024 updates, monthly generic rates are a three-month moving average. Since then metformin's figure has moved in small steps, rising from 1.30 cents in January 2025 to 1.46 cents that September, and staying between 1.40 and 1.47 cents in every month of 2026 so far.

Why the price stays low

Competition arrived early and in bulk. GxRadar counted abbreviated new drug applications (ANDAs) in FDA's Drugs@FDA data⁶ that cover a single-ingredient, immediate-release metformin 500 mg tablet. There are 36. Thirteen were approved in the six days from January 24 to January 29, 2002, among them ANDA 075972⁶, and 16 were approved that year in all. Fifteen of the 36 still list the 500 mg tablet as a marketed prescription product. Counting every form and strength, including extended-release tablets and oral solutions, FDA's data show 103 approved single-ingredient metformin ANDAs, 57 with at least one product still marketed. Our approvals tracker counts generic approvals across all drugs.

CMS's Medicare Part D Spending by Drug⁷ data list 29 manufacturers for generic immediate-release metformin in 2024. FDA economists found in a December 2019 analysis⁸ that with six or more generic makers, prices ran more than 95 percent below the brand's price before generic entry. Metformin has been far past that point for the entire NADAC era. Our explainer on why generic prices fall as competitors enter covers the pattern.

Volume is steady. Medicare Part D paid for about 24 million claims of generic immediate-release metformin in each year from 2020 through 2024, while claims for the extended-release version grew by more than 40 percent.

Spending per claim is based on gross drug cost, which CMS says in its methodology⁵ includes ingredient cost, dispensing fees and sales tax and excludes manufacturer rebates. A claim can also cover any number of tablets, so these figures are not comparable with the per-tablet NADAC above.

The 2020 recalls and the immediate-release tablet

Metformin made news in 2020, when manufacturers recalled extended-release products found to contain the impurity N-nitrosodimethylamine (NDMA) above FDA's acceptable intake limit. On its metformin NDMA update page⁹, FDA said its testing "has not shown NDMA in immediate release (IR) metformin products (the most commonly prescribed type of metformin)." The openFDA enforcement data¹⁰ contain 47 recall records for metformin products citing NDMA, 40 of them reported in 2020, and every one describes an extended-release product. Our recall tracker uses the same data, and our history of nitrosamine impurities explains how the problem was found.

NADAC for the 500 mg tablet shows no clear reaction. It ranged from 1.56 to 1.67 cents a tablet across 2020. FDA's shortage list, as of October 30, 2026, did not include immediate-release metformin. It did carry an extended-release metformin tablet entry, posted October 22, 2026, with the status "To Be Discontinued," according to our shortage tracker.

What sits on top of a cent and a half

For a drug this cheap, the ingredient is the smallest part of what a prescription costs the system. Most state Medicaid programs pay pharmacies an ingredient cost plus a professional dispensing fee, according to CMS's state reimbursement table for the quarter ending September 2026¹¹. New Jersey's fee in that table is $10.92 and New York's is $10.18.

Run the arithmetic on 730 tablets at October 2026 NADAC. As 12 monthly fills in New Jersey Medicaid, the dispensing fees would total $131.04 against $10.71 for the tablets. As four 90-day fills, the fees would total $43.68. Those figures say nothing about what a patient pays, which depends on coverage, deductibles and the pharmacy's own prices. Our explainers on 90-day supplies and how pharmacies get paid go further, and the NADAC explainer covers what the survey excludes.

The moving average that has smoothed metformin's figure since December 2024 is still described as temporary. CMS's methodology⁴ says it will continue "until further notice" and that the agency plans to solicit stakeholder input on a more permanent way to handle volatility.