In the United States, the list price of a vial of insulin rose nearly eightfold between 2001 and 2018 and then fell by about three quarters almost overnight. Humalog, Eli Lilly's rapid-acting insulin, cost about $35 a vial in 2001 and $234 in 2015. It stayed near $275 from 2018 through 2022, then dropped to $66.40 at the end of 2023. For most people, that sticker price was never the amount they paid. In 2026, Medicare caps what a beneficiary pays for each covered insulin at $35 for a month's supply, and manufacturer programs offer similar limits to some commercially insured and uninsured patients.
The history is easier to follow once three prices are kept apart: the list price a manufacturer publishes, the net price it keeps after discounts, and the out-of-pocket cost a patient pays at the pharmacy. They moved in different directions for most of the past decade, which is why headlines about insulin prices so often seem to contradict each other. All figures below are in U.S. dollars and are not adjusted for inflation.
From a one-dollar patent to modern insulins
The story of insulin's price usually begins with a dollar, but that dollar bought a patent, not a vial. After the discovery of insulin in Toronto in the early 1920s, its discoverers sold their rights to the University of Toronto for $1 each.[1] The gesture still colors the price debate, but it says nothing about what a dose cost then or should cost now.
The product also changed beyond recognition. Insulin is a small protein hormone, and the first commercial supplies were extracted from the pancreases of cattle and pigs. In 1982 the FDA approved Humulin, human insulin made by genetically engineered cells and the first medicine produced with recombinant DNA technology. Insulin analogues followed: Humalog in 1996 and Lantus in 2000.[2] An analogue is insulin with a few amino acids changed so that it acts faster or lasts longer after injection.
Each generation was a new product with its own manufacturing, dosing, and patent protection, sold in vials and prefilled pens that hold different amounts. A century-long price series for "insulin" therefore mixes different medicines. The comparisons that hold up follow one product in one presentation, and Humalog, with prices published by both Congress and its manufacturer, is the clearest case.
How much did insulin prices rise?
The list price of a Humalog vial rose from about $35 in 2001 to $234 in 2015, according to the Senate Finance Committee, which cited the increase when it opened a bipartisan investigation into insulin pricing in 2019.[3] That is a nearly sevenfold rise for one brand. It is not an average across insulins, and it is not what patients spent each month.
Lilly's own disclosures pick up the series from there. The year-end list price of a Humalog U-100 vial (U-100 means 100 units of insulin per milliliter) was about $275 in every year from 2018 through 2022. Over the same five years, the average net price Lilly received per vial, after rebates, discounts, and other payments to the supply chain, fell from $62 to $40.[4] By 2022, Lilly kept roughly one dollar in seven of the advertised price.
| Year | Year-end list price per vial | Annual average net price per vial |
|---|---|---|
| 2018 | $275 | $62 |
| 2019 | $275 | $60 |
| 2020 | $275 | $47 |
| 2021 | $275 | $40 |
| 2022 | $275 | $40 |
| 2023 | $66 | $26 |
A flat list price and a falling net price look paradoxical until one asks where the difference went. The answer lies in how insulin is bought.
Why the list price and the patient's bill came apart
The list price, formally the wholesale acquisition cost, is the starting point for negotiation. Between the manufacturer and the pharmacy sit pharmacy benefit managers (PBMs), companies that run drug coverage for health plans and decide which medicines appear on a plan's formulary, its list of covered drugs. Manufacturers compete for a place on that list largely by offering rebates, paid as a share of the list price.
The Senate Finance Committee's 2021 report concluded that this arrangement rewarded high list prices. A larger list price made room for a larger rebate, and a larger rebate helped win preferred formulary placement, so manufacturers had little reason to lower the sticker price even as their net revenue fell.[5] The investigation examined business incentives; it did not estimate what insulin costs to make.
Patients felt the result through their insurance design rather than through the net price. Someone with a fixed copayment was shielded from the list price. Someone with a high deductible, or with coinsurance charged as a percentage of the price, often paid a share of the full $275 even though no one else in the chain did. Rebates lowered what plans spent without necessarily lowering what that person paid at the counter, which is how a medicine whose net price was falling became a symbol of unaffordable care.
The 2023 to 2024 price cuts
The three largest insulin makers cut U.S. list prices within a year of one another. Lilly moved first: in March 2023 it announced a $25 list price for its non-branded Insulin Lispro vial from May 1, 2023, along with cuts to Humalog and Humulin.[6] Its January 2024 price disclosure lists a 10 mL Humalog U-100 vial at $66.40.[7]
Novo Nordisk cut the list price of NovoLog and NovoLog Mix 70/30 by 75% from January 1, 2024, bringing a NovoLog vial to $72.34, with 65% reductions for Novolin and Levemir.[8] Sanofi reduced the list price of Lantus U-100 by 78% and Apidra by 70% on the same date.[9]
| Product | List-price change | Effective date |
|---|---|---|
| Lilly non-branded Insulin Lispro U-100 vial | $25 per vial | May 1, 2023 |
| Humalog U-100, 10 mL vial | $66.40 per vial | December 30, 2023 |
| NovoLog vial | 75% reduction; $72.34 per vial | January 1, 2024 |
| Lantus U-100 | 78% reduction | January 1, 2024 |
The cuts narrowed the gap between list and net price rather than erasing revenue that manufacturers had been keeping: Humalog's 2023 net price of $26 was already far below its old list price (Table 1). What changed most was the price seen by patients whose costs were tied to the list, such as those paying toward a deductible.
What patients pay for insulin in 2026
A Medicare beneficiary pays no more than $35 for a month's supply of each covered insulin, with no deductible. The limit applies to insulin covered under Part D and to insulin used in a qualifying pump covered under Part B. It is set per product, so a person who uses both a long-acting and a rapid-acting insulin can pay up to $35 for each.[10]
The $35 figure is a ceiling rather than a fixed charge. In 2026, Part D cost-sharing for insulin is the lowest of $35, 25% of the plan's negotiated price, or 25% of the Medicare maximum fair price for insulins covered by drug price negotiation. In a CMS example, an insulin with a $100 negotiated price costs the patient $25.[11]
Outside Medicare, the rules depend on insurance and on voluntary manufacturer programs. The Lilly Insulin Value Program caps a monthly prescription at $35 for eligible people who have commercial insurance or no insurance, but excludes anyone enrolled in a government health program and has its own product and eligibility conditions.[12] Unlike Medicare's cap, which is set by law, such programs can change their terms.
What people actually pay is often far below these ceilings. Lilly reported that in 2025 the average out-of-pocket cost per dispensed vial was $4.83 for Humalog U-100 and $4.08 for its non-branded Insulin Lispro, based on IQVIA pharmacy claims data; earlier years were restated to account for the number of vials per prescription.[13] These averages describe prescriptions that were filled. They cannot show how many people rationed insulin or went without, and a month's treatment often takes more than one vial.
For an individual, the useful comparison is the same insulin, strength, package, and quantity under their own coverage or savings program. A pharmacist or insurer can give that figure; switching to a different insulin to save money is a clinical decision for a prescriber.
How U.S. insulin prices compare with other countries
Before the cuts, insulin in the United States was far more expensive than elsewhere. Using 2022 data, RAND found that U.S. manufacturer list prices were 9.71 times those of 33 other OECD countries combined. After an estimate of U.S. rebates and discounts, the gap narrowed to 2.33 times.[14]
Both ratios compare the same basket of insulin products, priced per unit of insulin rather than per vial or pen, because package sizes differ between products and countries. RAND drew on IQVIA MIDAS sales data and had to estimate U.S. net prices, since individual rebates are confidential.[14] The two ratios tell the same story as Humalog's price history: most of the American premium sat in the list price, and the choice between list and net prices changes the answer by a factor of four. Because the data predate the 2023 to 2024 cuts, neither ratio describes the market in 2026.
Taken together, insulin's price history is less a single rising curve than a widening split between what was advertised, what was earned, and what was paid. The list-price cuts closed much of the first gap, and the Medicare cap and manufacturer programs limited the last one for many patients. Any insulin price quoted today is meaningful only once four things are known: which insulin, how much of it, in which year, and who is paying.
