What is the difference between Medicare Advantage and Medigap?

Medigap and Medicare Advantage cover the same gap in opposite ways, and you can only hold one. Here is how to compare a full year of each.

Updated September 3, 2026 · 4 min read · by Gerino Alejos

Key points

You can hold a Medigap policy or a Medicare Advantage plan, not both.
Original Medicare pays about 80 percent of most services, so a $50,000 hospital stay leaves about $10,000 on your side, with no cap.
For six months after your Part B starts, any Medigap policy in Texas is open to you with no health questions. After that, a company can turn you down.

Both cover the same gap, in opposite ways. Original Medicare pays about 80 percent of most services and puts no ceiling on your share of the rest. Medigap pays that share for you, and an Advantage plan hands the job to a private company.

That share has no limit. On a $50,000 hospital stay, your 20 percent is about $10,000.

You cannot hold both. It is one or the other.

Medigap replaces your share

With a Medigap policy, or supplement, you keep Original Medicare. Medicare pays its part of a bill, and the policy pays the deductibles and coinsurance left behind. A deductible is what you pay before coverage pays. Coinsurance is your share of the bill after that.

Medigap does not cover prescriptions. You add a standalone Part D plan, a drug plan you buy on its own. See what a Medigap policy is.

Any doctor or hospital in the country that accepts Medicare.
No network to stay inside, no referral to see a specialist, and almost no prior authorization, where the plan approves care first.
Steady costs. With a comprehensive policy you rarely see a bill.
Two monthly premiums, or bills, one for the supplement and one for the drug plan.
No dental, vision or hearing.

Advantage replaces the delivery

With an Advantage plan, a private company runs your Medicare. It pays the claims, and most plans fold in drug coverage and extra benefits.

Often no premium, or monthly bill, beyond the Part B premium you already pay.
Drug, dental, vision and hearing coverage commonly bundled in.
A yearly out of pocket maximum, a cap on what you can be asked to pay in a year.
A network, the list of doctors and hospitals the plan has contracts with, plus referrals and prior authorization.
Copays, a set amount for each visit or service, so your cost rises with the care you use.

How to compare the cost in a good year and a bad year

Comparing monthly premiums points you the wrong way. Add up a full year on each side.

Medigap path: twelve months of supplement premium, twelve months of drug plan premium, and the Part B deductible. It barely moves with the care you use, so it covers your quietest year and your hardest at once.
Advantage path: twelve months of any plan premium, plus the plan's yearly out of pocket maximum. That is your worst year. A healthy year can land near zero.

Then ask which risk you would rather carry. The Advantage number moves with your health, up to the cap in a hard year. The Medigap number sits still.

The underwriting clock

For six months after your Part B starts, you can buy any Medigap policy sold in Texas with no health questions. After that window, a Texas insurer can use underwriting, looking at your health history and saying no.

Later on, moving from an Advantage plan to a Medigap policy is the step that may not be open to you. The other direction almost always is. If you are torn, that difference is a reason to start on the supplement side.

Which tends to fit whom

Medigap tends to fit people who travel or live elsewhere part of the year. It fits people seeing specialists for a long term condition, people set on a certain doctor or hospital outside a network, and people who want no surprises.

An Advantage plan tends to fit people whose doctors are already nearby and in the network. It fits people who want dental and vision included, people who feel healthy and would rather skip another monthly bill, and people who do not mind referrals.

In Hidalgo County the networks are deep and most people here are on Advantage plans, which is a fair reason it works well locally. Check your own doctors anyway. See how to check them and a six question worksheet.

For a starting point before you run the totals, see your Medicare options. A licensed agent calls you back with the plans available at your address.

Run both year totals with your doctors and prescriptions in front of you, then pick the risk you would rather carry. To go through it together, call our McAllen office at (956) 687 3334, or use the ZIP form on this page.

Not sure which path fits you? Enter your ZIP code and a licensed agent from McAllen Insurance Group calls you back to walk through the plans available at your address, in English or Spanish.

See my optionsor call (956) 687 3334

Common follow-up questions

Can I have both a Medigap policy and an Advantage plan?

No. It is not allowed, and paying for both would waste money, since the supplement cannot pay anything while you are in an Advantage plan.

Which is cheaper?

Month to month, an Advantage plan almost always costs less. Across a year with major medical bills, Medigap often comes out lower. It depends on your health, not on the plans.

Can I try Advantage and switch to Medigap if I do not like it?

Sometimes. There is a trial right, a one time chance to go back, mainly if you joined an Advantage plan at 65 and drop it within twelve months. Outside those rules you may face underwriting.

Want this looked at properly?

We are an independent agency in McAllen serving Hidalgo, Cameron and Starr counties. There is no obligation to talk it through.

Call (956) 687 3334

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