Does Medicare Cover Insulin? The $35 Monthly Cap and How Part D Insulin Works

Yes, Medicare covers insulin, and thanks to the Inflation Reduction Act, most people on Medicare now pay no more than $35 for a one-month supply of a covered insulin product. The cap applies whether you are in your deductible, initial coverage, or catastrophic phase. But there are real limits to how the $35 cap works, and the fine print matters if your specific insulin isn't on your plan's formulary.

Here is what actually determines what you pay, how the Part B side of insulin coverage works for pump users, and how to make sure your plan covers the product you already use.

Summary: Medicare's insulin coverage means (1) a $35 monthly cap per covered insulin, (2) no Part D deductible on insulin, (3) the cap only applies to insulins on your plan's formulary, and (4) insulin used in a pump is billed under Part B with the same $35 cap.

The Short Answer: What You'll Pay for Insulin on Medicare

If your insulin is on your Part D plan's formulary, you'll pay $35 or less for a 30-day supply. That's it. Not $35 after you meet a deductible, not $35 during initial coverage only. It's a hard cap that applies across every phase of your drug coverage for the year.

The same $35 cap also applies to insulin used in a traditional pump, which is billed under Part B rather than Part D. So whether you inject with a pen or use a pump, the ceiling is the same.

How the $35 Cap Actually Works

The Inflation Reduction Act rewrote the rules for insulin cost sharing on Medicare. Since 2023, and unchanged for 2026, every Part D plan is required to cover at least one insulin product in each dosage form (vial, pen) and each insulin type (rapid-acting, short-acting, intermediate-acting, long-acting, and pre-mixed).

For any covered product, the plan is prohibited from charging more than $35 for a one-month supply. There's also no Part D deductible on insulin, which used to be a hidden cost — you'd hit a $500-plus deductible before your copay dropped.

To put the change in perspective, before the cap took effect many enrollees were paying $150 to $400 a month out of pocket for a single insulin, especially brand-name analogs like Lantus, Humalog, or Novolog. Today the ceiling on a covered insulin is $35 flat.

What the $35 cap does not do is force every plan to cover every insulin. Which brings us to the piece most people miss.

When Your Specific Insulin Isn't on the Formulary

Every Part D plan has a formulary — the list of drugs it covers. Plans change formularies every year. An insulin that was on your plan's list in January can be dropped, moved to a different tier, or replaced with a competitor's product for the following plan year.

If your specific insulin isn't on your plan's formulary, the $35 cap doesn't help you. You're either paying full retail price or you're switching to a covered alternative.

"It's a good idea to review your Part D coverage every year with a licensed broker for this reason," says Angela Ellington, a licensed Medicare agent in Fontana, California. "Formulary-covered insulins are capped at $35, but it's possible that the brand you use is no longer on your Part D formulary. The Inflation Reduction Act created a $2,000 catastrophic limit, but if your drug is not on the formulary, it won't count toward that calculation either."

That's the part that catches people off guard. The $2,000 annual out-of-pocket cap on Part D only applies to what you spend on covered drugs. A non-formulary insulin doesn't count toward it, and there's no ceiling on what you pay.

Formulary status isn't the only thing that shifts between plans. Coverage rules do too. "Every Part D plan has its own specific formulary drug list, and different rules," says Mark Boone, a licensed Medicare agent in Rochester, Minnesota. "A drug that didn't require prior authorization under your old plan might have different coverage rules under a new one, thus the need for a prior authorization." So even if your insulin technically stays covered when you switch plans, you may end up waiting on paperwork before your first fill goes through.

Part B vs. Part D: Which Covers Your Insulin?

This trips up a lot of new enrollees. The route your insulin travels depends on how you take it:

• Insulin pens and vials for self-injection — covered under Medicare Part D. This is where most insulin users get their coverage.
• Insulin used in a traditional insulin pump (DME) — covered under Part B as durable medical equipment. Same $35 cap, but billed through your Part B benefit.
• Insulin administered in a hospital or provider's office — covered under Part B for that specific administration.

"Medicare can cover wearable medical devices for chronic conditions," says Sam Silva, a licensed Medicare agent in West Palm Beach, Florida. "Insulin pumps are covered under Part B if medically necessary for managing diabetes. You may need to meet specific criteria, and coverage can depend on the device's use and how it's prescribed." In practice that means your doctor's documentation matters just as much as your plan choice when a pump is involved.

If you have Original Medicare plus a Medigap plan, your Part B insulin pump costs may be partially or fully covered by your supplement after Medicare's share. If you're on a Medicare Advantage plan, the Part B insulin still runs through your plan's Part B benefit rules.

What About Diabetes Supplies?

Insulin is only part of the picture. Diabetes supplies fall in a few different places depending on what you use:

• Continuous glucose monitors (CGMs), test strips, lancets, and blood glucose meters — covered under Part B as durable medical equipment when you meet medical necessity requirements.
• Syringes, pen needles, alcohol swabs, and gauze — covered under Part D if you get your insulin under Part D.
• Insulin pump supplies — covered under Part B along with the pump itself.

"Medicare may cover a continuous glucose monitor and related supplies if you have diabetes, your doctor prescribes it, and you meet certain medical requirements," says Mary Brown, a licensed Medicare agent in Somerset, New Jersey. "Under Part B, you would typically pay 20% after the deductible unless you have additional coverage."

That 20% Part B coinsurance is where a lot of diabetes patients end up with unexpected costs on CGMs. A Medigap plan usually picks it up. Some Medicare Advantage plans include CGMs as a supplemental benefit, but you should confirm the specific device you use is covered before enrolling.

CGM coverage itself took a long time to arrive. "Medicare tends to take a slow, cautious approach to new technologies of all kinds," says Don Golding, a licensed Medicare agent in Sugar Land, Texas. "A good example is the adoption of continuous glucose monitors. It took several years for Medicare to cover these devices, but now they are widely used and covered in most Medicare plans." Expect the same pattern with newer diabetes tech — the first year or two of a device on the market is usually the hardest for coverage.

How to Pick a Part D Plan If You Take Insulin

The $35 cap makes plan selection more forgiving than it used to be, but the wrong plan can still cost you real money. A few things to check every year during the fall Annual Enrollment Period:

1. Look up your specific insulin on the plan's formulary. Not just "insulin" — the exact brand and dosage form. Plans list them by name.
2. Check which pharmacies the plan considers preferred. Non-preferred pharmacies can charge different amounts even for capped drugs.
3. Review all your other prescriptions. The $35 cap only helps with insulin. Everything else runs on normal Part D tier pricing.
4. Watch for prior authorization or step therapy. Even a covered insulin can require paperwork before the plan approves the first fill.

The Medicare Plan Finder at medicare.gov lets you enter your medications and see estimated annual costs across every plan in your area. If you'd rather not do it yourself, comparing Part D plans with a local licensed agent is free and usually the fastest way to see all your options side by side.

Extra Help for Lower-Income Enrollees

If your income is limited, you may qualify for Extra Help (also called the Low Income Subsidy), which drops your insulin copay well below $35 and covers most other drug costs too. As of 2024, the program expanded so that anyone up to 150% of the federal poverty level gets the full subsidy — no partial-benefit tier anymore. It's worth checking eligibility even if you were denied in past years.

Extra Help usually isn't the only program in play. "There are several programs designed specifically for people with limited income to help with Medicare premiums and other costs," says Chad Smith, a licensed Medicare agent in Lexington, Kentucky. "The main ones are the Medicare Savings Programs, administered through Medicaid, plus the Extra Help program for prescription drugs." The MSPs handle Part B premiums and, at higher tiers, Part A and cost-sharing too — so stacking MSP eligibility with Extra Help can knock a serious chunk out of your total Medicare costs before you even factor in the insulin cap.

Bottom Line

Medicare covers insulin, and the $35 monthly cap is real. The catch is that it only applies to insulins your plan actually lists on its formulary, and plans change those lists every year. Insurance companies release their official 2027 plan formularies around October 1, so once Annual Enrollment opens on October 15, pull up your Part D plan's 2027 formulary and confirm your specific insulin is still on it before enrollment closes December 7. If it's not, this is the year to switch — because the cap doesn't do you any good if your product isn't covered.