Medicare Supplement

How Medicare Supplement fills Original Medicare gaps in Lowell

LOWELL, Mass. — If you've ever looked at a Medicare bill and wondered why Original Medicare didn't pay the whole thing, you've bumped into the reason Medicare Supplement insurance exists. Also called Medigap, it's a private policy that helps pay some of the out-of-pocket costs Original Medicare (Part A and Part B) leaves behind — things like coinsurance, copays, and hospital deductibles.

Medigap, in plain English

Medigap doesn't replace Medicare. It works alongside it. Medicare pays its share first, then your Medigap policy pays its share of what's left, based on the letter plan you picked.

How the standardized letters work

In most states, Medigap policies are standardized by the federal government and labeled with letters: A, B, C, D, F, G, K, L, M, and N. Two rules make this simpler than it looks:

• Same letter, same benefits. A Plan G from one company covers the exact same gaps as a Plan G from another. The price and customer service can differ; the benefits cannot.
• Newer enrollees have fewer choices. If you became eligible for Medicare on or after January 1, 2020, you can't buy Plans C or F, because those plans covered the Part B deductible. People who were already eligible before that date can still buy them if available.

Plans K and L have lower premiums but ask you to share more of the cost until you hit a yearly out-of-pocket limit. Plan N has copays for some office and emergency visits. Plans G and (for older enrollees) F tend to be the most comprehensive. There's no single "right" letter — the right one depends on your health, budget, and how much predictability you want.

Massachusetts, along with Wisconsin and Minnesota, standardizes its Medigap plans a little differently than the rest of the country. Lowell residents will see Massachusetts-specific plan designs (like Core and Supplement 1) rather than the letter plans used elsewhere. The idea is the same — standardized benefits, sold by private insurers — but the labels look different.

What Medigap does not cover

This is where people get tripped up. Medigap is designed to fill gaps in Original Medicare, not to add new categories of coverage. A standard Medigap policy generally does not cover:

• Prescription drugs (you'd need a separate Part D plan)
• Routine dental, vision, or hearing care
• Long-term care (like a nursing home stay for custodial reasons)
• Private-duty nursing
• Eyeglasses or hearing aids

Also important: you cannot use Medigap with a Medicare Advantage plan. Medigap only works with Original Medicare. If you're on Medicare Advantage (Part C), a Medigap policy can't pay your Advantage plan's copays, and it's actually illegal for someone to sell you one while you're enrolled in Advantage, unless you're switching back to Original Medicare.

The enrollment window that matters most

The single most important date for Medigap is the start of your Medigap Open Enrollment Period — the six months that begin the first month you're both 65 or older and enrolled in Part B. During this window, you have "guaranteed issue" rights: insurers must sell you any Medigap policy they offer at their best available rate, regardless of your health history.

Miss that window, and in most states insurers can use medical underwriting. That means they can look at your health and charge more, offer fewer plans, or decline coverage altogether. Massachusetts has stronger consumer protections than many states — including continuous or annual open enrollment for Medigap under state rules — but the safest bet nationwide is still to enroll when you first become eligible.

How Medigap fits with the rest of Medicare

A quick recap of how the pieces connect in 2026:

• Original Medicare (Part A and Part B) pays most of your hospital and doctor costs, but not all.
• Medigap helps pay what Original Medicare leaves for you.
• Part D is a separate drug plan. For 2026, the Part D out-of-pocket cap is $2,100, the maximum Part D deductible is $615, and the old "donut hole" is gone — replaced by a simpler three-phase design that started in 2025. There's also the optional Medicare Prescription Payment Plan, which lets you spread drug costs into monthly payments.
• IRMAA is an income-based surcharge on Part B and Part D premiums; for 2026 it kicks in above $109,000 in income for a single filer.
• Medicare Advantage (Part C) is a different path — a private plan that replaces Original Medicare for how your care is delivered. If you go this route, you don't buy Medigap.

Plan availability is set at the county level. Lowell is in Middlesex County, where Medicare beneficiaries generally have a wide range of Medigap carriers and Medicare Advantage options to compare. The specific counts change every year, so it's worth checking the Plan Finder at medicare.gov before you decide.

Common mistakes to avoid

• Waiting past your six-month Medigap window. This is the mistake that costs people the most, because it can lock them out of coverage later.
• Assuming Medigap covers drugs. It doesn't. Pair it with a Part D plan.
• Trying to hold both Medigap and Medicare Advantage. You can only use Medigap with Original Medicare.
• Shopping only on price. Because benefits within a letter are identical, price matters — but so does the insurer's history of rate increases and their customer service.