- Part D caps covered insulin at $35 for a 30-day supply and covers oral diabetes drugs plus injection supplies like syringes — but test strips, lancets, and meters are billed to Part B as durable medical equipment, not Part D.
- Insulin users can get up to 300 test strips per 3 months through Part B; non-insulin users get up to 100.
- Your 2026 Part D out-of-pocket maximum is $2,100 for covered drugs — after that, you pay $0 for the rest of the year.
If you have diabetes and Medicare, you're probably juggling two systems at once: Part D for your medications and Part B for your testing supplies. Here's exactly how coverage splits between them in 2026 — and how to avoid surprise bills.
Part D covers your insulin and diabetes drugs
Any insulin your plan covers costs you no more than $35 for a 30-day supply in 2026 — and the deductible can't be charged on it. This applies to injectable insulin and inhaled insulin that are on your plan's formulary. If you use a durable insulin pump, the insulin in the pump is covered under Part B instead, with similar cost protections.
Part D also covers:
- Oral diabetes medications such as metformin, glipizide, Januvia, Jardiance, and Farxiga
- GLP-1 drugs prescribed for diabetes (for example Ozempic, Trulicity, Mounjaro) when medically necessary and on your plan's formulary — note Medicare does not cover these same drugs when prescribed for weight loss alone
- Injection supplies: syringes, needles, alcohol swabs, gauze, and insulin inhaler devices
- Disposable insulin pumps in some cases
Every plan has its own formulary and tiers, so the first thing to check is whether your insulin and drugs are listed — brands can differ from plan to plan.
Test strips and meters go through Part B, not Part D
This is the split that confuses almost everyone. Medicare draws a strict line between testing supplies and injection supplies:
- Part B (durable medical equipment): blood glucose meters, test strips, lancets, lancet devices, and control solutions
- Part D (pharmacy benefit): insulin, diabetes pills, and injection supplies
Even though you may pick up test strips at the same pharmacy counter, they're billed through Part B. That means you owe the Part B deductible and 20% coinsurance — not your Part D copay. A few practical rules:
- The pharmacy or supplier must be enrolled in Medicare — otherwise Medicare won't pay.
- Your doctor must document the diabetes diagnosis and prescribe the supplies (new prescriptions each year).
- Quantity limits: up to 300 test strips and 300 lancets every 3 months if you use insulin; up to 100 of each if you don't. Your doctor can document medical necessity for more.
Four ways to keep diabetes costs down in 2026
- Check your formulary during AEP (Oct 15 – Dec 7). Plans change which insulins they prefer every year. If your insulin moves to a non-preferred tier, your other costs can jump even with the $35 cap.
- Ask about Extra Help. If your income and assets are limited, this federal program can cut your Part D premium, deductible, and drug copays dramatically. It also covers the late enrollment penalty.
- Use the Medicare Prescription Payment Plan. If your drugs cost a lot early in the year, you can opt into monthly capped payments instead of one big pharmacy bill. It doesn't lower the total — but it smooths the cash flow.
- Compare pharmacies and mail order. Your plan's preferred pharmacies and 90-day mail-order supplies can meaningfully lower what you pay per fill.
Watch your plan if you take diabetes GLP-1s
Drugs like Ozempic and Mounjaro sit on expensive specialty tiers, and plans may require prior authorization or step therapy before covering them. If your doctor prescribes one for type 2 diabetes, confirm the prior authorization is approved before you leave the pharmacy — otherwise you could face the full retail price at the counter. And remember: because Medicare excludes weight-loss drugs by law, a GLP-1 prescribed only for weight management is not covered at all.
What the $2,100 out-of-pocket cap means for you
In 2026, once your spending on covered Part D drugs reaches $2,100, you pay $0 for covered drugs for the rest of the calendar year. There's no more "donut hole" phase. If you take high-cost diabetes medications, you may reach the cap by mid-year — after which every covered refill is free. Track your progress toward the cap on your Part D explanation of benefits (EOB).
Bottom line: Part D handles your insulin (capped at $35/month), diabetes pills, and injection supplies; Part B handles meters and test strips — know the split, check your formulary during open enrollment, and let the $2,100 cap work for you.