When You Shouldn’t Choose a Medicare Supplement (Medigap) Plan in 2026

By Dr. Harman Virk, DO — Board‑Certified Internal Medicine, The Modern Medicine Group (Fresno, CA) 

Medicare Supplement (Medigap) plans have a great reputation—and for good reason. They can reduce surprise bills, work with any doctor who accepts Medicare, and make your coverage more predictable.

But there are also times when a Medicare Supplement plan is the wrong choice.

In this guide, we’ll explain in plain language:

• 3 clear situations when you shouldn’t be on a Medigap plan

• What to consider instead (like Medicare Advantage or D-SNP plans)

• How timing, health history, and budget affect your options

• Where to get help in the Fresno area

Quick note: This article is educational only. It’s not financial, legal, or insurance advice. Please review your personal situation with a licensed agent or counselor and your medical provider.

⸻

Table of Contents

1. Medigap vs. Medicare Advantage: Simple Overview

2. Reason #1: You’re Dual Eligible (Medicare + Medicaid)

3. Reason #2: You Missed Your Medigap Window and Can’t Pass Underwriting

4. Reason #3: Medigap Premiums Don’t Fit Your Budget

5. When Medicare Coverage and Addiction Treatment Overlap

6. How Fresno Patients Can Decide What’s Right

7. Frequently Asked Questions

⸻

Medigap vs. Medicare Advantage: Simple Overview

Before we get into the “don’t do this” situations, here’s a quick refresher:

Original Medicare (Parts A & B)

• Part A = hospital coverage

• Part B = doctor visits, tests, outpatient care

• You usually pay:

  • A monthly Part B premium

  • Deductibles

  • 20% coinsurance on many services

• No cap on how high your out-of-pocket costs can go in a bad year

  
  

Medicare Supplement (Medigap)

A Medigap plan is a separate policy from a private insurer that helps pay some or most of the deductibles and coinsurance that Original Medicare leaves behind. You must have Parts A & B to buy one. 

• Works with any provider who accepts Medicare

• You still need a separate Part D drug plan

• You pay a monthly Medigap premium in addition to Part B

• In most states, you have a one-time 6-month Medigap Open Enrollment Period when you first start Part B at 65 after that, you may face health questions (underwriting). 

Medicare Advantage (Part C)

A Medicare Advantage plan (HMO or PPO):

• Replaces Original Medicare A & B with a private plan

• Uses a network of doctors and hospitals

• Usually includes Part D drug coverage

• Often has low or $0 monthly premiums

• Sets a yearly maximum out-of-pocket limit (something Original Medicare doesn’t do)

Both paths can work well—but not for everyone, and not in every situation.

The rest of this article focuses on three times when Medigap is usually the wrong choice.

⸻

Reason #1: You’re Dual Eligible (Medicare + Medicaid)

If you have both Medicare and Medicaid (or Medi-Cal in California), a Medicare Supplement plan is usually unnecessary, and in some cases insurers aren’t allowed to sell you one.

What “dual eligible” means

You’re considered dually eligible if:

• You have Medicare (Part A and/or B), and

• You qualify for full Medicaid benefits or a Medicare Savings Program that helps pay your premiums and cost-sharing. 

In this situation:

• Medicare pays first for covered services

• Medicaid (Medi-Cal) pays last, and may cover your Part B premium plus many copays and deductibles

Why Medigap doesn’t make sense here

For full dual-eligible patients:

• Most of the out-of-pocket costs Medigap is designed to cover are already handled by Medicaid, and

• Regulations generally prohibit issuing a Medigap policy to someone who receives full Medicaid benefits, because it doesn’t add real value. 

In short, you’d be paying a premium for something that doesn’t give you meaningful extra protection—and may not even be allowed.

A better fit: D-SNP Medicare Advantage plans

If you’re dual eligible, look at Dual-Eligible Special Needs Plans (D-SNPs):

• Built specifically for people with both Medicare and Medicaid

• Coordinate coverage between the two programs

• Often add extra benefits: rides, dental, vision, hearing, OTC allowances

• Usually have very low or $0 premiums

If you’re dual eligible, your “no-brainer” in 2026 is to skip Medigap and explore D-SNP options instead.

⸻

Reason #2: You Missed Your Medigap Window and Can’t Pass Underwriting

You get one big “easy button” when you first start Part B at 65: a 6-month window when you can buy most Medigap plans without health questions. After that, most people have to pass medical underwriting—and many with serious conditions are denied.

The 6-month Medigap Open Enrollment Period

Under federal law, your Medigap Open Enrollment Period:

• Starts the month you’re both 65 or older and enrolled in Part B, and

• Lasts 6 months

• During this time, Medigap insurers must sell you a policy and can’t charge more because of your health.

This is the ideal time to decide if Medigap is right for you.

What happens after that window closes

Once those 6 months are over, in most states:

• Insurers can ask detailed health questions

• They can review your medical records and medications

• They can deny your Medigap application or charge higher premiums based on pre-existing conditions.

This can be a shock for people who:

1. Started on a Medicare Advantage plan at 65,

2. Stayed on it for a few years, then

3. Decide they want the freedom of a Medigap plan instead.

If you now have serious heart disease, cancer, lung disease, insulin-dependent diabetes, or other complex conditions, underwriting may block the switch.

Is this you?

Ask yourself:

• Did I start Part B more than 6 months ago?

• Am I currently on a Medicare Advantage plan?

• Have I developed new or serious medical issues since then?

If the answer is “yes” across the board, getting a Medigap plan approved may be difficult or impossible under current rules.

What to do instead

If Medigap isn’t realistically available to you:

• Focus on finding the best Medicare Advantage plan for your situation

• Check: are your doctors and hospitals in-network, and are your medications covered?

• Ask a local counselor (HICAP/SHIP) or trusted broker if you qualify for any special “guaranteed issue” rights to get a Supplement despite your health history

If your 6-month Medigap window is long gone and your health is complex, it often makes more sense to optimize your Advantage plan instead of chasing a Supplement you may not qualify for.

⸻

Reason #3: Medigap Premiums Don’t Fit Your Budget

Medigap plans can be excellent—but they’re not cheap. When you add up your Part B premium, Medigap premium, and drug plan premium, you may easily cross $300 per month. If that number doesn’t fit your budget, Medigap can actually increase financial stress instead of reducing it.

What Medigap really costs

Typical monthly costs for someone using Medigap might include:

• Part B premium – set annually by Medicare

• Medigap premium – varies by age, ZIP code, tobacco use, and plan letter

• Part D drug plan – depends on medications and formulary

Many people end up with a total in the $300+ per month range once everything is stacked, especially with popular plans like G and N.

For retirees on a fixed income, that can be a big chunk of the monthly budget.

Risks of stretching too far

If you “stretch” to afford Medigap:

• You may cut back on essentials (food, utilities, medications)

• You might end up dropping the Medigap policy after a year or two when money gets tight

• Once you drop it, getting another Medigap policy later may require underwriting again

In other words, an unsustainable Supplement is not a safe long-term solution.

A safer alternative if money is tight

If Medigap isn’t affordable, compare:

1. Original Medicare only (A & B, no supplement) – usually the cheapest monthly, but with uncapped 20% coinsurance risk.

2. Medicare Advantage – often $0 or low monthly premiums, includes a Part D plan, and sets a yearly maximum out-of-pocket limit on covered services.

From a risk standpoint, a well-chosen Advantage plan is usually much safer than going with A & B only, because there is at least a cap on your worst-case spending.

If Medigap premiums don’t comfortably fit your budget, a strong Medicare Advantage plan is usually a better financial match.

⸻

When Medicare Coverage and Addiction Treatment Overlap

For some patients, Medicare questions show up at the same time as worries about alcohol, prescription medications, or other substances—either for themselves or a loved one.

In those situations, the coverage type matters, but so does actually getting help.

Here in Fresno, a local resource like New Life Recovery can provide:

• Medical detox

• Residential treatment

• Outpatient and continuing care

• Support for co-occurring mental health concerns

If a loved one on Medicare is struggling with alcohol or other substances, you might combine medical care at The Modern Medicine Group with addiction treatment at a program such as New Life Recovery a Fresno-based addiction and mental health treatment center

⸻

How Fresno Patients Can Decide What’s Right

Here’s a simple process you can use before your appointment:

1. Write down your doctors and clinics Mark which ones you absolutely want to keep.

2. Make a medication list Include name, dose, and how often you take it.

3. Be honest about your monthly budget What can you comfortably spend on premiums each month?

4. Check where you are in the timeline

   • Are you within your first 6 months of Part B at 65+?

   • Are you already on an Advantage plan?

   • Have you ever applied for Medigap before?

5. See if you qualify for help Ask about Extra Help, Medicaid (Medi-Cal), or Medicare Savings Programs if your income is limited.

6. Bring everything to your visit at The Modern Medicine Group We can’t sell you plans, but we can explain how each option might affect your real-world care—referrals, imaging, procedures, and medications.

⸻

Frequently Asked Questions

Is a Medicare Supplement plan always better than Medicare Advantage?

No. Medigap usually gives more freedom and more predictable costs, but with higher monthly premiums and a separate drug plan. Medicare Advantage may be better if:

• Your budget is tight

• Your doctors are in the plan’s network

• You like having extra benefits (dental, vision, gym, etc.)

The “best” choice depends on your health, doctors, and budget.

 Can I switch from Medicare Advantage to Medigap later?

Sometimes, but it’s not guaranteed.

You can apply for Medigap any time of year, but after your initial 6-month Medigap window, most states allow insurers to use medical underwriting, and they can deny your application. Some states have special protections, but they’re limited.

What if I lose Medicaid—can I then get a Medigap plan?

Losing Medicaid doesn’t always give you a permanent guaranteed right to buy a Medigap plan. Rules vary by state, and a lot depends on your prior coverage history. If you’re about to lose Medi-Cal or a Medicare Savings Program, talk to a local SHIP/HICAP counselor quickly to see what rights you have.

 What should I bring to my appointment at The Modern Medicine Group?

Bring:

• All insurance cards (Medicare, Advantage, Medigap, Medicaid/Medi-Cal, etc.)

• A list of medications

• Any letters from your plan about coverage changes

• Your questions about referrals, tests, or upcoming procedures

This lets your clinician give advice that fits both your health needs and your coverage.

⸻

Final Thought

Medicare Supplement plans are powerful tools—but they’re not for everyone. In particular, you should think twice (or not at all) about Medigap if:

• You’re dual eligible (Medicare + Medicaid)

• You’ve missed your Medigap window and can’t pass underwriting

• The premiums don’t realistically fit your budget

In those cases, your energy is better spent picking the right Medicare Advantage plan and staying closely connected to your care team.