Medicare Part C (Medicare Advantage) covers everything Original Medicare covers, plus often adds dental, vision, hearing, and prescription drugs. Part D covers outpatient prescription medications. Together, they represent how most Medicare beneficiaries get broader coverage than Parts A and B alone can offer. Here’s how each one works and what you can expect to pay.
What Part C (Medicare Advantage) Covers
A Medicare Advantage plan replaces Original Medicare. It must cover every medically necessary service that Part A (hospital insurance) and Part B (medical insurance) cover. That includes hospital stays, doctor visits, lab tests, preventive screenings, outpatient surgery, durable medical equipment, and home health care. Private insurance companies run these plans, but Medicare sets the rules they follow.
The real draw of Part C is the extras. Most plans add benefits that Original Medicare doesn’t provide at all:
- Routine dental care such as cleanings, exams, and sometimes dentures or extractions
- Vision coverage including eye exams and allowances for glasses or contacts
- Hearing benefits like hearing exams and discounts or credits toward hearing aids
- Fitness programs such as gym memberships or wellness discounts
Not every plan offers the same extras, and the generosity of these benefits varies widely by plan and region. A dental benefit on one plan might cover two cleanings a year while another covers major procedures like crowns. You’ll want to compare plans in your area during enrollment.
One thing Part C doesn’t fully take over: hospice care. If you need hospice services, Original Medicare steps in to cover those costs even while you’re enrolled in a Medicare Advantage plan. The same applies to certain clinical research trials.
How Prescription Drugs Fit Into Part C
Most Medicare Advantage plans bundle prescription drug coverage (Part D) directly into the plan. These are sometimes called MAPD plans. The specifics depend on the type of plan you choose:
- HMO and PPO plans usually include drug coverage. If you want prescriptions covered, you must use the drug benefit built into the plan. You can’t pair these with a separate standalone Part D plan.
- Special Needs Plans (SNPs) always include Part D drug coverage.
- Private Fee-for-Service (PFFS) plans sometimes include drug coverage. If yours doesn’t, you can join a separate Part D plan.
- Medical Savings Account (MSA) plans never include drug coverage. You’ll need a standalone Part D plan if you want prescriptions covered.
This matters because choosing the wrong plan type could leave you without drug coverage or lock you out of getting it separately.
What Part D Covers
Part D covers outpatient prescription medications, meaning drugs you pick up at a pharmacy or receive through mail order. Every Part D plan, whether standalone or bundled into a Medicare Advantage plan, maintains a formulary: a list of covered drugs organized into tiers. Lower tiers cost you less, higher tiers cost more.
A typical formulary looks like this:
- Tier 1 (lowest cost): most generic drugs
- Tier 2 (medium cost): preferred brand-name drugs
- Tier 3 (higher cost): non-preferred brand-name drugs
- Specialty tier (highest cost): very expensive drugs, often for complex conditions
Plans can structure their tiers differently, so the same medication might sit on Tier 2 with one insurer and Tier 3 with another. Before enrolling, check whether your specific prescriptions are on the plan’s formulary and which tier they fall into. This single step can save you hundreds or thousands of dollars a year.
What Part D Does Not Cover
Federal law excludes certain categories of drugs from Part D coverage entirely. You won’t find coverage for medications used for weight loss or weight gain, drugs used for cosmetic purposes or hair growth, over-the-counter medications (with the exception of insulin and insulin supplies), cough and cold symptom relief products, or prescription vitamins and minerals other than prenatal vitamins and fluoride preparations. These exclusions apply to every Part D plan, not just some of them.
The $2,000 Out-of-Pocket Cap for Drugs in 2025
Starting in 2025, Part D plans cap your annual out-of-pocket drug spending at $2,000. This is a major change. Previously, people taking expensive medications could face costs well above that amount, partly because of a coverage gap (sometimes called the “donut hole”) where you paid a larger share of drug costs. That coverage gap has been eliminated.
Now the benefit works more simply. You pay your deductible and copays during an initial coverage phase. Once your total out-of-pocket spending hits $2,000 for the year, you pay nothing more for covered prescriptions for the rest of that calendar year. Many plans also let you spread those costs across monthly payments rather than paying large amounts upfront at the pharmacy.
What You’ll Pay for Part C
You must continue paying your Part B premium even after joining a Medicare Advantage plan. That’s non-negotiable. On top of that, many Part C plans charge their own monthly premium, though some plans have $0 premiums. A $0 premium doesn’t mean $0 costs. You’ll still face copays, coinsurance, and deductibles when you use services.
Every Medicare Advantage plan is required to set a yearly maximum on your out-of-pocket spending for Part A and Part B services. In 2025, that cap cannot exceed $9,350 for in-network services. For plans that allow out-of-network care (like PPOs), the combined in-network and out-of-network limit tops out at $14,000. Once you hit that ceiling, the plan pays 100% of your covered Part A and Part B services for the rest of the year. Original Medicare has no equivalent cap, which is one of the main financial reasons people choose Medicare Advantage.
When You Can Enroll or Switch Plans
You can join, switch, or drop a Medicare Advantage or Part D plan during the Annual Enrollment Period, which runs from October 15 through December 7 each year. Changes you make during this window take effect January 1.
There’s also a Medicare Advantage Open Enrollment Period from January 1 through March 31. During this window, if you’re already in a Medicare Advantage plan, you can switch to a different Medicare Advantage plan or drop back to Original Medicare and pick up a standalone Part D plan. You can only make one change during this period.
Outside these windows, you generally can’t change your coverage unless you qualify for a Special Enrollment Period triggered by specific life events like moving to a new area, losing other coverage, or qualifying for Medicaid.
Choosing Between Part C and Original Medicare
The choice comes down to what matters most to you. Medicare Advantage plans offer the convenience of bundled coverage (medical, drugs, dental, vision) under one plan with a built-in spending cap. The tradeoff is network restrictions. Most plans require you to use specific doctors and hospitals, and some require referrals to see specialists.
Original Medicare lets you see any provider who accepts Medicare, anywhere in the country, with no referrals needed. But it doesn’t cover dental, vision, or hearing, has no out-of-pocket maximum, and requires a separate Part D plan for drug coverage. Many people on Original Medicare also buy a Medigap (supplemental) policy to help cover cost-sharing, which adds another premium.
If you take multiple medications, compare formularies carefully. A plan with a low monthly premium but high-tier placement for your drugs could cost more overall than a plan with a slightly higher premium that covers your medications at a lower tier.