Medicare Supplement plans have strict rules about what they can and cannot cover
A Medicare Supplement policy must not contain benefits that duplicate what Original Medicare already covers, or that Medicare has explicitly prohibited. Federal law sets these boundaries to prevent you from paying for overlapping coverage and to keep the market transparent.
The main rule is straightforward: Medigap plans cannot pay for anything Medicare Part A and Part B do not cover, except for the specific gaps that Medigap is designed to fill — like coinsurance, copayments, and deductibles. They also cannot offer benefits that Medicare has ruled out of bounds, such as coverage for services deemed not medically necessary or experimental treatments that Medicare itself will not pay for.
Understanding what is forbidden helps you spot misleading marketing and know what you actually need to cover out of pocket.
Key Takeaways
- Medigap plans cannot cover services that Original Medicare does not cover, with rare exceptions for limited international emergency care.
- Plans cannot duplicate Part A or Part B benefits — they can only fill the gaps Medicare leaves, such as deductibles and coinsurance.
- Medigap cannot cover prescription drugs; you need Part D for that, which is a separate enrollment.
- Plans cannot offer benefits for services Medicare has determined are not medically necessary or are experimental.
- If a Medigap plan advertises coverage outside these boundaries, it is not a legitimate federally-approved plan.
Benefits that Medigap cannot legally include
Medigap plans are limited to filling specific gaps in Original Medicare coverage. They cannot add new benefits that Medicare itself does not recognize. For example, if Medicare does not cover routine dental work, a Medigap plan cannot offer dental coverage. The same applies to vision care, hearing aids, and long-term care — these are outside Medicare's scope, so Medigap cannot include them either.
This is a hard boundary set by federal law. The 10 standardized Medigap plans (labeled A through N) are designed around this rule. Each plan fills different combinations of the same gaps — the Part A deductible, the Part B deductible, coinsurance amounts — but none of them add benefits that Medicare does not already recognize.
If you see a plan advertised as "Medigap" that claims to cover dental, vision, or hearing, it is not a real Medicare Supplement. It may be a different type of plan, such as a Medicare Advantage plan, or it may be a scam.
Why prescription drugs are not part of Medigap
Prescription drug coverage is handled separately through Medicare Part D, not through Medigap. This is intentional. When you turn 65 or first become may be able to access for Medicare, you have a window to sign up for Part D. If you miss that window and do not have other creditable drug coverage, you may pay a penalty when you do sign up later.
Some Medigap plans were allowed to include limited drug coverage under older rules, but those plans are no longer sold to new people. If you are shopping for a Medigap plan now, none of the current standardized plans include prescription drug benefits. You must handle drug coverage through Part D or through a Medicare Advantage plan, which combines medical and drug coverage in one plan.
Services Medicare has not approved cannot be in Medigap either
If Medicare determines that a service is experimental, not medically necessary, or outside the scope of covered care, then Medigap cannot cover it. This protects you from paying premiums for coverage that would never actually pay out, because the underlying service is not recognized by Medicare.
For example, if Medicare does not cover a particular type of surgery because it has not been proven effective, a Medigap plan cannot offer to pay for it. The same applies to treatments that Medicare considers cosmetic or elective rather than medically necessary. Medigap follows Medicare's definitions of what counts as covered care.
The one exception: limited international emergency coverage
Most Medigap benefits must stay within the boundaries of what Medicare covers. However, there is one narrow exception: some Medigap plans offer limited coverage for emergency medical care outside the United States. This is not a benefit Medicare itself provides, but federal rules allow Medigap plans to add it.
The coverage is typically limited to the first 60 days of a trip outside the U.S., and it covers only emergency care — not routine or planned treatment. The amount covered varies by plan, and not all plans include this benefit. If international travel is important to you, check the plan documents to see whether it offers this coverage and what the limits are.
How to spot a plan that is breaking the rules
If a plan advertises benefits that sound too broad, it may not be a legitimate Medigap plan. Red flags include claims of coverage for dental, vision, hearing aids, long-term care, or any service that Medicare does not cover. Another warning sign is a plan that claims to cover prescription drugs as part of the Medigap benefit itself (rather than directing you to Part D).
To verify that a plan is real, check the plan name and number against the list of standardized Medigap plans on Medicare.gov. All legitimate plans are labeled with a letter (A through N) and a company name. If the plan does not match one of these 10 standard designs, it is not a Medicare Supplement, even if it is marketed that way.
You can also call Medicare directly at 1-800-MEDICARE to ask whether a specific plan is federally approved. If someone is selling you a plan that promises benefits outside these rules, report it to your state insurance commissioner or to the Centers for Medicare & Medicaid Services.
What you do need to cover separately
Because Medigap cannot include certain benefits, you need to plan for them on your own. Prescription drugs require Part D enrollment. Dental, vision, and hearing care are not covered by Medicare or Medigap, so you either pay out of pocket or purchase separate dental and vision plans through private insurers.
Long-term care — such as nursing home or in-home information for daily living — is not covered by Medicare, Medigap, or Part D. Some people purchase long-term care insurance separately, while others plan to pay out of pocket or rely on Medicaid if their assets are depleted. This is a major gap to think about as you plan for aging.
Frequently Asked Questions
Can a Medigap plan cover dental or vision care?
No. Medigap plans cannot cover dental, vision, or hearing care because Medicare itself does not cover these services. If you need these benefits, you must purchase separate plans or pay out of pocket. Some employers or unions offer retiree dental and vision plans, which is another option to explore.
What if I see a plan advertised as Medigap with drug coverage?
Older Medigap plans sold before 2006 were allowed to include drug coverage, but those plans are no longer sold to new people. If you are shopping now, any legitimate Medigap plan will not include prescription drugs. Drugs are covered through Part D or through a Medicare Advantage plan instead.
Does Medigap cover long-term care like nursing homes?
No. Neither Medicare nor Medigap covers long-term care or information with daily living. You would need to purchase a separate long-term care insurance policy, pay out of pocket, or eventually rely on Medicaid if your assets run low. This is an important gap to plan for separately.
Can Medigap cover services that Medicare says are experimental?
No. Medigap plans must follow Medicare's rules about what counts as medically necessary and covered care. If Medicare does not cover a treatment, Medigap cannot cover it either. This protects you from paying premiums for coverage that would never actually pay out.
How do I know if a plan is a real Medicare Supplement?
Real Medigap plans are labeled with a letter (A through N) and sold by insurance companies. You can verify any plan on Medicare.gov or by calling 1-800-MEDICARE. If a plan promises benefits outside these 10 standard designs, it is not a legitimate Medicare Supplement.