Medicare Advantage vs Medicare Supplement: What Is the Difference?

Medicare Advantage and Medicare Supplement Insurance sound similar, but they serve different purposes. Understanding that difference is the starting point for a useful plan comparison.

They belong to different coverage arrangements

Medicare Advantage is a private-plan alternative for receiving Medicare benefits. Medicare Supplement Insurance, or Medigap, works alongside Original Medicare to help pay certain costs that are your responsibility. It does not replace Original Medicare and cannot be used to pay Medicare Advantage cost-sharing.

How does Medicare Supplement work?

Medigap is sold by private insurers and helps with specified Original Medicare out-of-pocket costs. Standardized lettered plans have defined benefits, so compare the exact plan letter and insurer. Modern Medigap policies do not include prescription drug coverage; a separate Part D decision is often needed.

How does Medicare Advantage work?

A Medicare Advantage plan has its own costs and coverage rules. Most include Part D, and networks or prior authorization may apply. Medicare requires these plans to cover medically necessary services that Original Medicare covers, but you should review how those services are accessed under the specific plan.

Use this review worksheet

• Providers: which doctors and facilities do you want to keep, and who has confirmed participation?
• Prescriptions: where is drug coverage included, and have all medications been checked?
• Monthly payments: what does each part of the proposed arrangement cost?
• Using care: which deductibles, copayments or coinsurance need explaining?
• Travel: what happens when you receive routine care away from home?
• Enrollment: which applications and deadlines must be completed separately?

Keep the answers in one place. If an answer is uncertain, record it as a question rather than filling the gap with an assumption.

Medigap enrollment deserves early attention

Medicare describes a generally one-time six-month Medigap Open Enrollment Period beginning when you are 65 or older and have Part B. Outside that period or another protected situation, a policy may be unavailable or priced differently. Annual Medicare Open Enrollment does not itself guarantee acceptance into a Medigap policy.

Before leaving Medicare Advantage

Confirm the permitted Medicare plan-change window, any intended Medigap policy and the drug coverage arrangement. Coordinate start and end dates. Do not cancel existing coverage because you expect a supplement application to be accepted.

Focus the conversation on your needs

Bring your provider list, medication list, ZIP code and current plan documents. Ask for a comparison that explains both monthly cost and cost when receiving services. PureShield can help you review available options, but there is no universal best choice and no guarantee about premiums, benefits or acceptance.

If you want an independent explanation of enrollment rights, Medicare.gov and your State Health Insurance Assistance Program are useful official starting points.

Frequently asked questions

Continue your research

• Medicare Advantage vs Original Medicare: How to Compare Your Options
• Medicare Open Enrollment: What You Can Change Before December 7
• Turning 65? A Simple Guide to Medicare Enrollment
• PureShield health insurance help

Official sources

• Medigap basics
• Buying Medigap
• When Medigap can be purchased
• Medicare coverage arrangements
• Part D overview

Information checked October 6, 2026. Enrollment rules and plan details can change; confirm the guidance that applies before taking action. PureShield Insurance is an independent insurance agency, not Medicare, CMS, HealthCare.gov or a government agency, and is not endorsed by the federal government.