Medicare covers Mounjaro, but only under Part D (prescription drug coverage), and only if your plan includes it on the formulary

Mounjaro is a diabetes medication that lowers blood sugar and helps with weight loss. Medicare Part B does not cover it — Part B covers drugs given in a doctor's office or hospital, and Mounjaro is a self-injected medication you use at home. Instead, you need Part D prescription drug coverage to pay for it, the same way you would for any other take-home medication.

Not every Part D plan covers Mounjaro, and the ones that do may require you to meet certain conditions first. Your plan's formulary — the official list of drugs it will pay for — determines whether Mounjaro is available to you and at what cost. Some plans cover it right away; others require you to try a different diabetes drug first and show that it did not work for you.

Key Takeaways

  • Mounjaro is covered under Medicare Part D (prescription drug plans), not Part B, because you inject it yourself at home.
  • Your specific Part D plan's formulary determines whether Mounjaro is covered and what your out-of-pocket cost will be.
  • Many Part D plans require prior authorization — your doctor must submit paperwork showing why you need Mounjaro before the plan will pay for it.
  • Some plans use step therapy, meaning you must try and fail on a cheaper diabetes drug first before Mounjaro is covered.
  • You can switch to a different Part D plan during the annual enrollment period (October 15 to December 7) if your current plan does not cover Mounjaro or charges too much.

Check whether your current Part D plan covers Mounjaro

Start by finding your plan's formulary. You can do this three ways: call the customer service number on the back of your Medicare card, visit your plan's website and search for the formulary, or go to Medicare.gov and use the Plan Finder tool. When you search, look for "tirzepatide" — that is the generic name for Mounjaro — because some formularies list it that way.

When you find Mounjaro on the formulary, note the tier it is on. Tier 1 drugs cost the least; Tier 5 drugs cost the most. Also check whether the plan lists any restrictions, such as "prior authorization required" or "step therapy applies." These restrictions mean your doctor will need to do extra paperwork before the plan will cover it.

If Mounjaro is not on the formulary at all, your plan will not pay for it. In that case, you have two options: pay for it out of pocket (Mounjaro costs around $900 to $1,100 per month without insurance, though the manufacturer offers a coupon that can lower this), or switch to a different Part D plan that does cover it.

Get prior authorization from your doctor if your plan requires it

Prior authorization means your doctor must submit a form to your insurance plan explaining why you need Mounjaro instead of a cheaper alternative. The plan reviews this form and decides whether to approve it. This usually takes 3 to 5 business days, though it can take longer if the plan asks your doctor for more information.

Your doctor's office typically handles this paperwork — you do not need to submit it yourself. Call your doctor's office and tell them you want to start Mounjaro and that your Part D plan requires prior authorization. They will know what to do. If your doctor is not familiar with the process, you can call your Part D plan's customer service line and ask them to send the prior authorization form directly to your doctor's office.

If the plan denies prior authorization, your doctor can appeal the decision. The appeal process varies by plan, but your doctor's office can guide you through it. You also have the right to request an independent review if you disagree with the plan's decision.

Understand step therapy requirements

Step therapy means your Part D plan will only cover Mounjaro after you have tried and failed on a different, usually cheaper diabetes medication first. For example, your plan might require you to try metformin or a GLP-1 drug like Ozempic before covering Mounjaro.

"Failed" typically means you took the drug for a set period — often 30 to 90 days — and either had side effects you could not tolerate or your blood sugar did not improve enough. Your doctor documents this in your medical record and submits it to the plan along with a request to cover Mounjaro instead.

If you have already taken another diabetes drug and it did not work for you, tell your doctor that when you discuss starting Mounjaro. Your doctor can include that history in the prior authorization request, which may speed up approval or help you skip the step therapy requirement altogether.

Switch Part D plans if your current one does not cover Mounjaro affordably

You can change Part D plans once a year during the annual enrollment period, which runs from October 15 to December 7. If your current plan does not cover Mounjaro, charges a very high copay, or requires step therapy you want to avoid, you can switch to a plan that offers better coverage.

Use the Medicare Plan Finder tool at Medicare.gov to compare Part D plans in your area. Enter Mounjaro (or tirzepatide) in the drug search box and filter by plans that cover it. The tool will show you the copay or coinsurance amount for each plan, so you can see which one costs the least. You can also call 1-800-MEDICARE to speak with a representative who can help you compare plans.

When you switch, your new coverage starts January 1 of the following year. Make sure you have enough of your current medication to last until then, or ask your doctor about a temporary alternative while you wait for the new plan to begin.

Understand your out-of-pocket costs under Part D

Your cost for Mounjaro depends on your Part D plan and where you are in the coverage year. In the early part of the year, you pay a copay or coinsurance (a percentage of the drug's cost) until you reach your plan's deductible. Once you meet the deductible, your plan begins to pay its share.

As you and your plan spend more on drugs throughout the year, you eventually enter the "coverage gap" — a range where you pay a higher percentage of the cost. In 2024, this gap begins after you and your plan have spent $5,850 together on covered drugs. However, Medicare has been lowering the amount you pay in the gap each year, so the exact percentage changes annually.

After you spend enough out of pocket to reach the catastrophic coverage threshold (around $7,400 in 2024, though this varies by year), your plan covers most of the cost for the rest of the year. Ask your Part D plan what your specific copay or coinsurance will be for Mounjaro, because it varies widely between plans.

Look into manufacturer coupons and patient information programs

Eli Lilly, the company that makes Mounjaro, offers a coupon that can reduce your copay to as little as $25 per month if you have commercial insurance or Medicare Part D coverage. This coupon is available at the Mounjaro website or through your pharmacy. Your pharmacist can help you explore it at the time you fill your prescription.

If you do not have Part D coverage or if your copay is still too high even with the coupon, Eli Lilly also runs a patient information program for people with limited income. You can learn about income limits and how the process works on the Mounjaro website or by calling the company directly. These programs can provide Mounjaro for free or at a reduced cost.

Some community health centers and nonprofit organizations also help uninsured or underinsured people pay for medications. Call 211 (a free referral service) or search for "patient information programs" plus your state name to find local resources.

Frequently Asked Questions

Does Medicare Part B ever cover Mounjaro?

No. Part B covers injectable drugs only if they are given to you in a doctor's office, hospital, or dialysis center. Because Mounjaro is a self-injected medication you use at home, it falls under Part D (prescription drug coverage) instead. If your doctor injects it for you in the office, that visit is covered under Part B, but the drug itself is still billed to Part D.

What if my doctor says I need Mounjaro but my Part D plan denies it?

Your doctor can file an appeal with your Part D plan. The plan must respond within 72 hours for urgent requests or 30 days for standard appeals. You also have the right to request an independent review by an outside organization if you disagree with the plan's decision. Your doctor's office can guide you through both processes.

Can I use a GoodRx coupon instead of my Part D coverage?

You can, but it is usually not the best choice. Part D coverage typically costs less than a GoodRx coupon, especially if you have already met your deductible. Compare the copay your Part D plan charges with the GoodRx price before you decide. Your pharmacist can help you check both prices at the register.

What happens to my Mounjaro coverage if I switch from Original Medicare to a Medicare Advantage plan?

Medicare Advantage plans (Part C) include prescription drug coverage, but each plan has its own formulary and rules. Some cover Mounjaro; others do not. If you are thinking about switching to Medicare Advantage, check whether the plan you are considering covers Mounjaro before you enroll. You can use the Medicare Plan Finder tool to compare coverage.

Can I get Mounjaro covered if I have both Medicare and Medicaid?

Yes, but the rules are complex and vary by state. Generally, Medicaid is the primary payer, meaning it pays first. If Medicaid covers Mounjaro in your state, that is your best option. If not, Medicare Part D may cover it as a secondary payer. Contact your state Medicaid office or call 1-800-MEDICARE to understand how coverage works in your situation.