Medicare covers most diabetes medications, but which part of Medicare pays and how much you owe depends on the type of drug, how it’s delivered, and which plan you’re enrolled in. Insulin, oral medications like metformin, newer injectable drugs, testing supplies, and even diabetes prevention programs all fall under different pieces of the Medicare system. Here’s how it breaks down.
Part B vs. Part D: Why It Matters
Medicare splits diabetes coverage between two programs, and understanding which one applies to your situation directly affects your costs. Part B covers items classified as durable medical equipment and the supplies that go with them. That includes insulin pumps, the insulin used in those pumps, continuous glucose monitors, and blood sugar testing supplies like test strips and lancets. You’ll typically pay 20% of the Medicare-approved amount after meeting your Part B deductible.
Part D is the prescription drug benefit, and it covers everything you pick up at a pharmacy or receive through mail order. That means insulin pens and vials, oral diabetes pills, and injectable medications like GLP-1 drugs. Part D is run by private insurance companies, so coverage details, copays, and formularies vary from one plan to another.
Insulin Coverage and the $35 Cap
Since January 1, 2023, people enrolled in a Medicare Part D plan pay no more than $35 for a one-month supply of each covered insulin product, whether picked up at a pharmacy or delivered by mail. The Part D deductible no longer applies to insulin, so that $35 cap kicks in from your very first fill of the year.
If you use an insulin pump covered under Part B, the same $35 monthly cap per insulin product took effect on July 1, 2023. Before these changes, some Medicare beneficiaries were paying hundreds of dollars a month for insulin, particularly during the Part D coverage gap. That gap no longer exists as of 2025.
Oral Diabetes Medications
Part D plans cover a wide range of oral diabetes drugs, but your out-of-pocket cost depends heavily on where a medication sits on your plan’s formulary. Most plans use a five-tier system, with Tier 1 being the cheapest and Tier 5 the most expensive.
Generic metformin, still the most commonly prescribed first-line diabetes drug, typically lands on Tier 1 or Tier 2, meaning copays are low, often just a few dollars. Brand-name medications in newer drug classes, such as SGLT2 inhibitors (which help the kidneys remove excess sugar) and DPP-4 inhibitors (which help the body produce more insulin after meals), tend to sit on Tier 3 or higher. That can mean significantly higher copays or coinsurance percentages. If a generic version exists for a drug in these classes, it will almost always cost less than the brand-name version on any given plan.
Because every Part D plan maintains its own formulary, a drug that’s Tier 3 on one plan could be Tier 4 on another, or might not be covered at all. Checking your specific plan’s drug list before enrollment, or before your doctor prescribes a new medication, saves surprises at the pharmacy counter.
GLP-1 Medications
GLP-1 receptor agonists, the drug class that includes semaglutide and tirzepatide, are covered by Medicare Part D when prescribed for type 2 diabetes, cardiovascular disease, or sleep apnea. Medicare is prohibited by law from covering these same drugs when prescribed solely for weight loss, even though some of them are FDA-approved for that purpose under different brand names.
These medications are expensive, often carrying list prices above $1,000 per month, so most Part D plans place them on higher formulary tiers. Many plans also require prior authorization, meaning your doctor needs to submit documentation justifying why you need the drug. Some plans use step therapy, which requires you to try less expensive medications first (typically metformin or another generic) before the plan will approve a GLP-1. If your initial request is denied, your doctor can appeal the decision with additional clinical information.
The 2025 Part D Out-of-Pocket Cap
Starting January 1, 2025, total out-of-pocket spending under Part D is capped at $2,000 per year. This is a major change for anyone taking expensive brand-name diabetes drugs. Once you hit that $2,000 threshold, you pay nothing for covered prescriptions for the rest of the calendar year.
The 2025 benefit structure works in phases. You first pay 100% of drug costs until you meet the $590 annual deductible (though insulin and vaccines are exempt from this deductible). After that, you pay 25% coinsurance during the initial coverage phase. Once your out-of-pocket spending reaches $2,000, you enter the catastrophic phase, where your cost sharing drops to zero. The old coverage gap, sometimes called the “donut hole,” has been eliminated entirely.
For someone taking a high-cost GLP-1 or brand-name SGLT2 inhibitor alongside insulin, this cap could save thousands of dollars compared to previous years.
Testing Supplies and Glucose Monitors
Medicare Part B covers blood sugar testing supplies for all beneficiaries with diabetes. The standard allowance every three months is up to 300 test strips and 300 lancets if you use insulin, or 100 test strips and 100 lancets if you don’t. If your doctor determines you need more frequent testing, Medicare will cover additional quantities with supporting documentation. You may need to keep a log showing how often you actually test.
Continuous glucose monitors (CGMs) are also covered under Part B as durable medical equipment. To qualify, you need a prescription from your doctor and must meet two conditions: you use insulin or have a history of problematic low blood sugar episodes, and you or your caregiver have completed training on how to use the device properly. Sensors and related supplies for the CGM are included in the coverage. After your Part B deductible, you’ll typically owe 20% of the approved cost.
Insulin Pumps
External insulin pumps fall under Part B as durable medical equipment. Medicare covers the pump itself, the insulin it uses, and related supplies like infusion sets. Your doctor will need to document that pump therapy is medically necessary for your situation. As with other Part B items, you’re responsible for 20% of the Medicare-approved amount, and the $35 monthly insulin cap applies to pump insulin as well.
Diabetes Prevention and Education
Medicare covers a structured prevention program for people who are prediabetic but haven’t yet developed type 2 diabetes. To qualify, you need a BMI of at least 25 (or 23 if you identify as Asian) and a recent blood test showing blood sugar levels in the prediabetic range. Specifically, that means an A1c between 5.7% and 6.4%, a fasting blood sugar between 110 and 125 mg/dl, or an oral glucose tolerance test result between 140 and 199 mg/dl, all within the past year.
The program itself includes a series of coaching sessions focused on diet, physical activity, and behavior changes to reduce your risk of progressing to type 2 diabetes. Medicare also covers diabetes self-management training for people who already have a diagnosis, which teaches skills like meal planning, medication management, and blood sugar monitoring.