Do I Need Medigap If I Have Medicare Advantage?

No. If you have a Medicare Advantage plan, you don’t need Medigap, and you generally can’t buy it. Medicare.gov says that when you’re getting started with Medicare, you can either buy Medigap or enroll in a Medicare Advantage plan, but you can’t have both.

That surprises a lot of people, because both are described as “extra” coverage. They aren’t the same kind of thing, and they don’t stack.

Why they don’t go together

Medigap, also called Medicare Supplement Insurance, is a private policy that helps pay out-of-pocket costs in Original Medicare, like copayments and coinsurance. It works alongside Original Medicare only.

A Medicare Advantage plan replaces Original Medicare. Medicare.gov describes it as another way to get your Medicare coverage besides Original Medicare. The plan sets its own copayments and out-of-pocket costs, so there are no Original Medicare cost-sharing amounts for Medigap to help pay.

Medicare.gov says insurance companies generally can’t sell you a Medigap policy if you have coverage through a Medicare Advantage plan. The one exception it lists is when you’re switching back to Original Medicare, or when your plan coverage will end before the Medigap policy’s effective date.

What each one needs from you

Both options require that you have Part A and Part B and keep paying your Part B premium. Medigap adds its own premium. Medicare.gov says you pay the insurance company a separate monthly premium for Medigap in addition to the Part B premium you pay to Medicare.

Two other Medigap details trip people up:

• It covers one person. If you and your spouse both want Medigap, each of you buys your own policy.
• It doesn’t include drug coverage. Medicare.gov says Medigap plans sold after 2005 don’t include prescription drug coverage. To have drug coverage with Medigap, you join a separate Medicare drug plan (Part D). Medicare Advantage plans, by contrast, usually bundle drug coverage in.

What people get wrong

Thinking a Medigap policy can fix a Medicare Advantage plan. It can’t. If your Medicare Advantage copays feel too high, Medigap isn’t an add-on that lowers them. The only way to get Medigap is to be in Original Medicare.

Assuming you can always go back. This is the big one. Switching from Medicare Advantage to Original Medicare is usually possible during an enrollment period. Getting a Medigap policy afterward is a separate matter. Medicare.gov says that outside your Medigap Open Enrollment Period, there’s no federal guarantee that an insurance company will sell you a policy. If you’re able to buy one, it may cost more because of past or present health problems.

Missing the Medigap Open Enrollment Period. Medicare.gov says this is a 6-month period that starts the first day of the month you’re 65 or older and signed up for Part B. During that window you generally can buy a policy without health questions getting in the way. Many people spend those months in Medicare Advantage and never think about it again, until they want out.

Not knowing about the trial rights. Medicare.gov describes two situations where you have a guaranteed right to buy a Medigap policy after leaving Medicare Advantage:

• You joined a Medicare Advantage plan when you were first eligible for Part A at 65, and within the first year of joining you decide to switch to Original Medicare.
• You dropped a Medigap policy to join a Medicare Advantage plan for the first time, and you’ve been in the plan less than a year.

In either case, Medicare.gov says you apply no earlier than 60 days before your Medicare Advantage coverage ends, and no later than 63 days after it ends. After the first year, those trial rights are gone.

Assuming your state follows the federal rules only. Medicare.gov tells you to check with your State Insurance Department about what rights you might have under state law. Some states offer protections beyond the federal ones, and they vary. If you’re thinking about leaving Medicare Advantage, find out what your state allows before you cancel anything.

How you actually leave Medicare Advantage

If you decide Original Medicare fits better, there are two yearly windows, and the Medigap piece works differently in each.

During Fall Open Enrollment, October 15 to December 7, Medicare says you can switch from a Medicare Advantage plan to Original Medicare, with the change taking effect January 1.

During the Medicare Advantage Open Enrollment Period, January 1 to March 31, you can drop your plan and go back to Original Medicare. Medicare is clear about the catch: you can’t use this period to buy Medigap coverage. If you drop your plan then, you can enroll in a standalone drug plan, but a Medigap policy is a separate question that depends on the rules above.

So leaving the plan and getting a Medigap policy are two different steps. The first is usually available. The second is what may require health questions.

Questions worth asking yourself

If you’re in Medicare Advantage and wondering about Medigap, it helps to sort out which situation you’re in:

• Have you been in the plan less than a year, having joined at 65? You may still have a trial right.
• Are you past that first year? Switching to Original Medicare is possible, but buying Medigap afterward may involve health questions, and the insurer can decline or charge more outside the guaranteed windows, depending on your state.
• Are you happy with your plan? Then Medigap isn’t something you need to chase.

Your State Health Insurance Assistance Program (SHIP) offers free counseling on exactly this question, and your State Insurance Department can explain your state’s rules.

Sources: Medicare.gov, “Learn How Medigap Works” (medicare.gov/health-drug-plans/medigap/basics/how-medigap-works); Medicare.gov, “When can I buy a Medigap policy?” (medicare.gov/health-drug-plans/medigap/ready-to-buy/when); Medicare.gov, “Illegal Medigap practices” (medicare.gov/health-drug-plans/medigap/ready-to-buy/how/illegal-practices); Medicare.gov, “Choosing a Medigap Policy” (medicare.gov/publications/02110-choosing-a-medigap-policy.pdf); Medicare.gov, “Understanding Medicare Advantage & Medicare Drug Plan Enrollment Periods” (medicare.gov/publications/11219-Understanding-Medicare-Advantage-Medicare-Drug-Plan-Enrollment-Periods.pdf).