Medicare Part D covers some weight loss drugs, but not all of them, and coverage depends on your specific plan
Medicare Part D is prescription drug coverage, and it does cover certain medications used for weight loss — but the list changes by plan and by year. The drugs most commonly covered are semaglutide (Ozempic, Wegovy), tirzepatide (Zepbound, Mounjaro), and phentermine, though your plan may cover others or exclude these. Coverage is not automatic: your doctor may need to show that the medication is medically necessary for you, and you may face a waiting period or a requirement to try other treatments first.
The amount you pay depends on your plan's formulary — the official list of covered drugs — and where the drug sits on that list. A drug on a lower tier costs you less out of pocket. Some plans require prior authorization, meaning your doctor must get approval from the insurance company before you fill the prescription. Others require you to try a different drug first. If your plan does not cover the drug your doctor recommends, you have options: you can ask your doctor to request an exception, switch to a different Part D plan during the open enrollment period, or pay out of pocket.
Key Takeaways
- Medicare Part D covers weight loss drugs like semaglutide and tirzepatide, but coverage varies by plan and changes year to year.
- Your plan's formulary determines which drugs are covered and how much you pay; you can view your plan's formulary on its website or by calling the plan directly.
- Your doctor may need to obtain prior authorization or show medical necessity before the prescription is filled.
- If your plan does not cover the drug your doctor wants to prescribe, you can request an exception, switch plans during open enrollment, or explore other options with your doctor.
- Cost-sharing for weight loss drugs varies widely — you may pay a copay, coinsurance, or a percentage of the drug's cost depending on the tier.
How to find out what your plan covers
The fastest way to know whether your specific Part D plan covers a weight loss drug is to check your plan's formulary online. Log into your plan's website using your Medicare number, or call the customer service number on the back of your insurance card. Have the drug name and strength ready — for example, "semaglutide 0.5 mg" — because different doses may be covered differently.
When you call or search online, ask three things: Is the drug on the formulary? What tier is it on (this tells you your cost)? Does it require prior authorization or step therapy (trying another drug first)? Write down the answers and the date you called, in case you need to reference them later.
If the drug is not on your plan's formulary, ask whether your plan covers similar drugs. For weight loss, plans may cover older medications like phentermine or orlistat instead. Your doctor can help you understand whether an alternative drug would work for your situation.
Prior authorization and step therapy requirements
Many Part D plans require prior authorization before covering newer weight loss drugs like semaglutide or tirzepatide. This means your doctor must submit a request to the insurance company, usually with information about your medical history and why the drug is necessary. The insurance company then decides whether to approve it. This process typically takes three to five business days, though it can be faster if your doctor marks it urgent.
Some plans also use step therapy, which means you may need to try and fail on a different, usually cheaper drug before the plan will cover the one your doctor prefers. For weight loss drugs, this might mean trying phentermine first, or trying diet and exercise counseling through a covered program. If step therapy applies to you, your doctor will know this when they submit the authorization request.
If your doctor believes the required step is not medically appropriate for you — for example, if you have a condition that makes phentermine unsafe — they can request an exception. The insurance company will review the request, usually within 72 hours. Your doctor should explain clearly why the alternative is not suitable and why the requested drug is necessary.
Cost-sharing: copays, coinsurance, and deductibles
What you pay for a weight loss drug depends on your plan's cost-sharing structure and the drug's tier. Most Part D plans use a four-tier system: generic drugs (lowest cost), preferred brand-name drugs, non-preferred brand-name drugs, and specialty drugs (highest cost). Weight loss drugs are often on tier 3 or 4, meaning your share of the cost is higher than for common generic medications.
You may pay a copay (a flat dollar amount per prescription) or coinsurance (a percentage of the drug's cost). For expensive drugs like semaglutide or tirzepatide, coinsurance can mean paying 25% to 33% of the cost out of pocket. A month's supply can cost several hundred dollars, so your share could be substantial. Some plans cap the amount you pay per prescription; others do not.
Your Part D deductible also applies. In 2024, the standard deductible is $545, though your plan may have a different amount. You must meet this deductible before your plan begins to pay its share. Once you reach the deductible, you then pay your copay or coinsurance for each prescription.
If your out-of-pocket costs are very high, you may reach the coverage gap (also called the "donut hole"), where you pay a larger share temporarily. After you and your plan together spend a certain amount on covered drugs, you enter this gap. In 2024, the gap begins at $5,850 in total drug costs. Once you spend enough out of pocket to reach the catastrophic coverage threshold (about $7,050 in 2024), your plan pays most of the cost again.
What to do if your plan does not cover the drug
If your plan's formulary does not include the weight loss drug your doctor recommends, you have several options. First, ask your doctor whether a covered alternative would work for you. Your plan may cover a different weight loss medication, an older drug like phentermine, or a medication originally developed for diabetes (like metformin) that can support weight loss.
Second, you can request a formulary exception. Your doctor submits a written request to your plan explaining why the non-covered drug is medically necessary and why covered alternatives are not appropriate for you. The plan must respond within 72 hours. If the plan denies the exception, you can appeal the decision. Your doctor can help you gather medical evidence to support the appeal.
Third, you can switch to a different Part D plan. During the annual open enrollment period (October 15 to December 7 each year), you can change to any Part D plan available in your area. Before you switch, check the new plan's formulary to confirm it covers the drug you need and compare the cost-sharing. You can also switch if you have a may have access to life event, such as a move or loss of other coverage.
Finally, you can pay out of pocket for the drug without using your Part D coverage. This means the cost does not count toward your deductible or out-of-pocket maximum, and you do not receive the plan's negotiated price. However, if you later want to use your Part D coverage for the same drug, you may be able to do so. Ask your plan about its rules on this before you pay out of pocket.
Medicare Advantage plans and weight loss drug coverage
If you have a Medicare Advantage plan (Part C) instead of Original Medicare with a separate Part D plan, prescription drug coverage is included in your Advantage plan. Advantage plans have their own formularies and may cover weight loss drugs differently than standalone Part D plans. Some Advantage plans cover weight loss medications more generously; others restrict them more.
To find out what your Advantage plan covers, check your plan's formulary or call the plan's customer service number. The process is the same as with standalone Part D: ask whether the drug is covered, what tier it is on, and whether prior authorization is required. If your Advantage plan does not cover the drug you need, you can switch to Original Medicare with a standalone Part D plan during the open enrollment period, though you would lose your Advantage coverage.
When Medicare Part D does not cover weight loss drugs at all
Some Part D plans do not cover weight loss medications for weight loss alone. These plans may cover semaglutide or tirzepatide only when prescribed for diabetes, not for weight management. This is because Medicare historically did not cover drugs prescribed primarily for weight loss, though this policy has been changing as these medications have become more common and more doctors prescribe them.
If your plan does not cover weight loss drugs under any circumstance, you have the same options as above: request an exception, switch plans, or pay out of pocket. You can also talk to your doctor about whether a covered medication for another condition (such as diabetes or high blood pressure) might also help with weight loss.
Questions to ask your doctor and your insurance plan
Before you fill a prescription for a weight loss drug, ask your doctor: Is this drug covered by Medicare Part D? Will my plan require prior authorization? Are there covered alternatives if my plan does not cover this one? What should I do if my plan denies coverage?
Ask your Part D plan: Is [drug name and dose] on my formulary? What tier is it on, and what will I pay? Does it require prior authorization or step therapy? If it is not covered, can I request an exception? When does my deductible reset, and how much have I already spent toward it this year?
Frequently Asked Questions
Does Medicare cover Ozempic or Wegovy for weight loss?
Some Medicare Part D plans cover semaglutide (Ozempic, Wegovy), but not all. Coverage depends on your specific plan's formulary. Your plan may cover it only for diabetes, only for weight loss, or for both. Call your plan or check its website to find out whether your plan covers it and what you would pay.
What if I cannot afford the copay or coinsurance?
If your cost-sharing is very high, you may be able to get help through the Part D Low-Income Subsidy program, which reduces premiums and out-of-pocket costs for people with limited income. You can also ask your doctor or pharmacist whether the drug manufacturer offers a patient information program or coupon that can lower your cost.
Can I use a GoodRx coupon or discount card instead of my Medicare Part D?
You can, but it is usually not a good idea. Using a discount card means the cost does not count toward your Part D deductible or out-of-pocket maximum, so you may end up paying more overall. Compare the price your plan would charge with the discount card price before you decide. Ask your pharmacist to show you both prices.
What happens to my coverage if I switch Part D plans?
When you switch plans, your new plan's formulary takes effect on January 1 of the following year (if you switch during open enrollment) or on the first of the month after your request is processed (if you switch due to a may have access to event). Any prescriptions you filled under your old plan do not transfer; you start fresh with your new plan's deductible and out-of-pocket costs.
Can my doctor appeal if my plan denies prior authorization?
Yes. If your plan denies prior authorization or a formulary exception, your doctor can file an appeal on your behalf. The plan must respond within 72 hours for urgent appeals or 30 days for standard appeals. Your doctor should include medical evidence explaining why the drug is necessary for you and why covered alternatives are not appropriate.