A Medicare supplement also known as Medigap insurance is sold by private insurance carriers. They can help pay some of your health care costs that Original Medicare will not cover, like copayments, coinsurance, and deductibles.
Some Medigap policies offer coverage for services that Original Medicare will not cover, such as medical care when you travel outside the United States. If you have Original Medicare and you buy a Medicare Supplement, Medicare will pay its part of the Medicare-approved amount for the covered health care. Then your Medigap policy pays its share. This would be determined by which Medigap plan you choose.
A Medigap policy is different from a Medicare Advantage Plan. Advantage plans are an alternative way to get Medicare benefits, while a Medigap policy will supplement your Original Medicare benefits.
Medigap policies will not cover long-term care, vision, dental care, hearing aids, eyeglasses, or private-duty nursing.