Medicare Plans
Medicare Advantage vs. Medicare Supplement in St. Louis, MO
In St. Louis, the choice usually narrows to two options. One is a Medicare Advantage plan, a single private plan with a low premium that covers everything. The other is a Medicare Supplement, or Medigap, which rides behind Original Medicare and pays what Medicare leaves.
Which one is right comes down to your doctors, your drugs, how often you leave town and how much you're willing to pay each month to know your costs ahead of time.
- Two ways to fill the gaps in Original Medicare
- Your hospital system usually settles the question
- The premium is only part of what you pay
- Free side-by-side pricing for St. Louis area residents
Get both paths priced for your doctors and drugs
Send us your doctors, your hospital and your prescriptions. A licensed insurance agent prices a Medicare Advantage plan and a Medigap plus Part D setup from the companies we represent, then calls you back during business hours with the full-year difference.
What to expect
Free review- A licensed agent calls you back during business hours, Mon-Fri, 8:30am-5:30pm CT
- Your doctors and prescriptions get checked before any plan is suggested
- No fee for our help, and your premium is the same either way
- No obligation to enroll, and no pressure if you'd rather stay put
Reviewed by the licensed insurance agents at St. Louis Senior Insurance. Last reviewed: October 2026. Office hours: Mon-Fri, 8:30am-5:30pm CT.
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Side by side
Where the two paths split
| Compare | Medicare Supplement Medigap · pairs with Original Medicare | Medicare Advantage Part C · all-in-one private plan | Part D Drug Plan Prescriptions only · add-on |
|---|---|---|---|
| What it covers | Your share of Part A and Part B costs, including deductibles, copays and coinsurance. | Hospital, medical and usually drugs, bundled into one plan with one card. | Prescription medications only. Nothing medical. |
| Doctor networks | None. Any provider in the U.S. who accepts Medicare. | HMO or PPO network. Confirm your BJC, Mercy or SSM Health doctors are in it. | Pharmacy network only. Preferred pharmacies usually cost less. |
| Monthly premium | Highest of the three, plus your Part B premium. | Often $0, plus your Part B premium. | Low monthly premium, plus your Part B premium. |
| Costs when you use care | Little to nothing after the Part B deductible on Plan G. | Copays per visit and per service, capped by an annual out-of-pocket maximum. | Deductible and tiered copays based on the plan's drug list. |
| Prescription drugs | Not included. You add a separate Part D plan for that. | Included in most St. Louis area plans. | This is the drug coverage. |
| Extras (dental, vision, hearing) | Not included. Buy standalone if you want them. | Commonly included, with allowances that vary a lot by plan. | Not included. |
| Health questions to enroll | None during your 6-month open enrollment; underwriting applies later. | None. Acceptance is guaranteed during a valid enrollment period. | None. |
| Best if you | Travel often, see specialists frequently, and want predictable bills. | Are settled with your local providers and want low premiums plus extras. | Chose Medigap or Original Medicare and need drug coverage. |
| Read more | Medicare Supplement details | Medicare Advantage details | Part D Drug Plan details |
Medicare Supplement
Medigap · pairs with Original Medicare
- What it covers
- Your share of Part A and Part B costs, including deductibles, copays and coinsurance.
- Doctor networks
- None. Any provider in the U.S. who accepts Medicare.
- Monthly premium
- Highest of the three, plus your Part B premium.
- Costs when you use care
- Little to nothing after the Part B deductible on Plan G.
- Prescription drugs
- Not included. You add a separate Part D plan for that.
- Extras (dental, vision, hearing)
- Not included. Buy standalone if you want them.
- Health questions to enroll
- None during your 6-month open enrollment; underwriting applies later.
- Best if you
- Travel often, see specialists frequently, and want predictable bills.
Medicare Advantage
Part C · all-in-one private plan
- What it covers
- Hospital, medical and usually drugs, bundled into one plan with one card.
- Doctor networks
- HMO or PPO network. Confirm your BJC, Mercy or SSM Health doctors are in it.
- Monthly premium
- Often $0, plus your Part B premium.
- Costs when you use care
- Copays per visit and per service, capped by an annual out-of-pocket maximum.
- Prescription drugs
- Included in most St. Louis area plans.
- Extras (dental, vision, hearing)
- Commonly included, with allowances that vary a lot by plan.
- Health questions to enroll
- None. Acceptance is guaranteed during a valid enrollment period.
- Best if you
- Are settled with your local providers and want low premiums plus extras.
Part D Drug Plan
Prescriptions only · add-on
- What it covers
- Prescription medications only. Nothing medical.
- Doctor networks
- Pharmacy network only. Preferred pharmacies usually cost less.
- Monthly premium
- Low monthly premium, plus your Part B premium.
- Costs when you use care
- Deductible and tiered copays based on the plan's drug list.
- Prescription drugs
- This is the drug coverage.
- Extras (dental, vision, hearing)
- Not included.
- Health questions to enroll
- None.
- Best if you
- Chose Medigap or Original Medicare and need drug coverage.
Local networks
How this plays out at St. Louis hospitals
-
Medigap: no network
If a doctor takes Original Medicare, your Medigap plan pays. That goes for BJC, Mercy, SSM Health, St. Luke's and doctors in other states, with no referrals. -
Advantage: the network decides
St. Louis Advantage plans don't all contract with the same hospital systems. Some include several, others lean on one. Plans offered in St. Charles County can also differ from those in the city or St. Louis County. -
Drug coverage works differently
Advantage plans usually build Part D in. With Medigap you buy a separate Part D plan and can shop it on its own each fall, which often saves money if you take a costly drug.
In the St. Louis area, the network question tends to come down to BJC (Barnes-Jewish, Missouri Baptist, Christian and Barnes-Jewish St. Peters), Mercy (Mercy Hospital St. Louis and Mercy Hospital South), SSM Health (Saint Louis University Hospital, DePaul, St. Clare and St. Joseph in St. Charles) and the independent St. Luke's in Chesterfield. If you're in cancer treatment, check your oncologist by name. Veterans who use the John Cochran or Jefferson Barracks VA medical centers can keep VA benefits with either path. The VA doesn't bill Medicare, though, so think about where you'd get care outside the VA. Check whether we cover your area on our service areas page.
Choose Advantage if
When Medicare Advantage makes sense
- You want the lowest premium, often $0 beyond Part B
- Your doctors and hospital are already in the plan's St. Louis network
- You'll use extras like dental, vision, hearing or a gym membership
- Copays don't bother you, as long as there's a yearly cap
- You get most of your routine care close to home
Choose Medigap if
When a Medicare Supplement makes sense
- You'd rather pay one steady premium than copays at each visit
- You see specialists in more than one hospital system, or split the year between St. Louis and another state
- You want to see any doctor who takes Medicare, with no referrals
- You're in ongoing treatment where copays would add up quickly
- You're in your six-month Medigap open enrollment and can join without health questions
The timing detail that catches people
You can join or change an Advantage plan each fall during Open Enrollment. Getting into a Medigap plan later usually means health questions, and the company can turn you down. Missouri's anniversary rule lets Medigap members switch companies, but it doesn't help someone moving over from Advantage. Keep that in mind before your first choice.
Total cost
Add up a full year of costs
A $0-premium Advantage plan still costs money once you use it. Add up likely copays for your regular checkups, specialists, scans and any planned surgery. Then compare that with a year of Medigap premiums plus a separate drug plan. For a healthy 66-year-old in Kirkwood or Webster Groves, Advantage often comes out ahead. For someone managing a long-term condition with frequent specialist visits, Medigap often costs less over twelve months.
We do that math with your own drug list and doctors. Start with the Medicare checklist, or read the mistakes to avoid before you sign. For free counseling on every plan in your county, Missouri SHIP answers at 800-390-3330.
Questions
Advantage vs. Medigap questions from St. Louis
Can I have Medicare Advantage and Medigap at once?
Which one costs less in St. Louis?
Do I keep paying for Part B either way?
Does Medigap cover my prescriptions?
If I start with Advantage, can I move to Medigap later?
Still on the fence?
Bring us your doctors and prescriptions. We'll price both paths for a full year and show you the gap in dollars.