Medigap Plan G at $178–$221/Month vs Medicare Advantage $0 Premium After the IRA's $2,000 Part D Cap: Which Costs Less for Specialty Drug Users in 2026
You Got a Renewal Notice. Now What?
Your Medigap Plan G premium just increased — again. Your insurance agent is mentioning a nearby Medicare Advantage plan with a $0 monthly premium. And somewhere in the back of your mind is a vague headline about the Inflation Reduction Act "capping drug costs at $2,000."
Here is the decision in front of you: Is the IRA's Part D savings enough to offset Medigap's rising premiums? Or is that $0-premium MA plan quietly more expensive once you factor in prior authorization delays, copays during a hospitalization, and formulary restrictions on your specialty medication?
Those three facts — IRA drug savings, Medigap premium increases, and MA's hidden costs — interact differently depending on what you take, what you spend, and where you live. This post runs the numbers.
What the IRA Actually Changed for Part D — Two Phases, Different Stakes
The Inflation Reduction Act made changes to Part D in two distinct waves, and conflating them causes confusion.
The 2024 change: Catastrophic coinsurance eliminated. Before 2024, once your drug spending crossed the catastrophic threshold (~$8,000 in total drug costs), you paid 5% coinsurance — with no ceiling. A beneficiary on a $3,200/month biologic could owe north of $5,000 in a year. The IRA eliminated that coinsurance entirely for 2024. A JAMA study highlighted by the Medicare Rights Center found this change — combined with an expansion of the Part D Low-Income Subsidy benchmark — measurably improved medication adherence among Medicare beneficiaries. When the cost of staying on your medication drops, people actually stay on it. That's not a small finding.
The 2025 change: Hard $2,000 annual OOP cap on Part D. Starting January 1, 2025, your total out-of-pocket liability for covered Part D drugs is capped at $2,000 per year — regardless of how expensive your drug regimen is. This applies to both standalone Part D plans and the Part D component built into Medicare Advantage plans.
Here is what that means in dollar terms for a beneficiary on a $3,200/month specialty biologic (think Humira, Enbrel, or an oral oncology agent):
| Year | Annual Drug List Price | Beneficiary OOP Estimate |
|---|---|---|
| 2023 (pre-IRA) | $38,400 | ~$5,200 |
| 2024 (catastrophic coinsurance eliminated) | $38,400 | ~$3,800 |
| 2025–2026 ($2,000 hard cap) | $38,400 | $2,000 |
The IRA saves this beneficiary roughly $3,200 per year compared to 2023. That number is central to the Medigap vs. MA comparison — because it reduces the cost of staying on Original Medicare with a standalone Part D plan.
Medigap Plan G Premiums: The Leap Is Real, and the Exit Is Dangerous
KFF Health News's recent analysis, "Medigap Premiums Leap, and Consumers Have Few Alternatives," correctly identifies the bind: premiums are rising, but for most beneficiaries outside their initial open enrollment window, leaving Medigap is a one-way door.
Toravine's analysis of 3,570 rows of Medigap rate data across states and age bands confirms the trajectory:
| Age Band | 2024 Avg Monthly Premium (Plan G) | 2026 Avg Monthly Premium | Change |
|---|---|---|---|
| 65–69 | $158 | $178 | +12.7% |
| 70–74 | $196 | $221 | +12.8% |
| 75–79 | $241 | $272 | +12.9% |
These are national averages. Individual state outcomes diverge sharply — Wisconsin's community-rated model holds premiums flat by age, while Florida and New York age-rated markets can price a 75-year-old 70% higher than a 65-year-old for identical coverage.
The trap KFF identified is the irreversibility. In 46 states, if you drop Medigap Plan G to try a $0-premium Medicare Advantage plan and later want to come back, insurers can decline your application or surcharge you based on health status. Outside of your 6-month Medigap Open Enrollment Window — which opens when you enroll in Part B at 65 — you have no guaranteed right to return. As discussed in our post on Medigap underwriting and the three enrollment windows that determine whether you can switch back to Original Medicare, this is one of the most consequential and least-discussed risks in Medicare.
The plan that looks expensive today may be the plan you cannot afford to lose.
The Full 12-Month Cost Stack: Three Scenarios
All three scenarios below assume a 68-year-old beneficiary in a medium-cost state, taking one specialty biologic at $3,200/month, with income below the 2026 IRMAA threshold of $106,000 for single filers. (Toravine's cms_medicare_irmaa dataset — 174 rows of CMS IRMAA bracket data — shows the Part B IRMAA surcharge adds $69.90–$419.30/month for single filers above $106K; if you're near that threshold, your total cost stack shifts materially.)
Scenario A: Original Medicare + Medigap Plan G + Standalone Part D
- Part B standard premium: $185.00/month
- Medigap Plan G (age 68, 2026 avg): $221.00/month
- Standalone Part D premium: $46.50/month (2026 national average from Toravine's cms_medicare_plan_premiums dataset, 1,236 rows)
- Part D OOP (specialty drug, IRA cap): $2,000
- Hospital/SNF cost-sharing: $0 (Plan G covers Part A deductible and all cost-sharing)
- Annual total: ($185 + $221 + $46.50) x 12 + $2,000 = $5,430 + $2,000 = $7,430
Scenario B: Medicare Advantage HMO, $0 Premium, Built-In Part D
- MA plan premium: $0/month
- Part B premium: $185.00/month (still required regardless of MA enrollment)
- Part D OOP (IRA cap applies to MA drug coverage too): $2,000
- MA plan MOOP (2026 HMO average, in-network): $5,250
- Estimated prior authorization friction cost for specialty biologic: $400–$800
- Annual total (no hospitalizations): $185 x 12 + $2,000 = $2,220 + $2,000 = $4,220
Scenario C: Medicare Advantage PPO, $89/month Premium, Built-In Part D
- MA PPO premium: $89/month
- Part B premium: $185/month
- Part D OOP: $2,000
- MA PPO MOOP (in-network, 2026 avg): $4,800
- Annual total (no hospitalizations): ($185 + $89) x 12 + $2,000 = $3,288 + $2,000 = $5,288
This is the kind of analysis Toravine runs for you — mapping your specific drug list against actual formulary tiers, your state's Medigap rate bands, and your local MA plan options — so you're not building this spreadsheet from scratch two weeks before Open Enrollment.
Why "No Hospitalizations" Is Doing Heavy Lifting in the MA Scenarios
Scenarios B and C look competitive until you get sick. Here is what changes:
| Event | Scenario A (Original Medicare + Plan G) | Scenario B (MA HMO, $0 Premium) |
|---|---|---|
| 3-day inpatient hospital stay | $0 (Plan G covers all Part A cost-sharing) | $1,200–$2,000 in daily copays |
| Skilled nursing facility, days 21–100 | $0 (Plan G covers SNF coinsurance) | $194/day average copay |
| Out-of-state specialist visit | Any Medicare-accepting provider nationwide | Out-of-network or not covered |
| Specialty biologic (prior auth required) | Part D standalone — auth required, no hospitalization incentive | Prior auth required; insurer manages both drug AND medical costs |
One 5-day hospitalization in Scenario B can add $3,000–$4,500 in copays — wiping out 12 months of premium savings versus Plan G. The 10-year picture for beneficiaries with chronic conditions looks markedly different. Our analysis of MA HMO vs. Original Medicare + Medigap Plan G over 10 years for chronic condition beneficiaries shows that by year 7 or 8, accumulated MA copays frequently close the gap — and in high-utilization years, exceed — cumulative Medigap premiums paid.
Prior Authorization: The Part D Cost That Doesn't Show Up in a Premium Comparison
The Medicare Rights Center's April 2026 report on MA prior authorization data — the first public release under CMS's 2024 transparency rule — is worth reading carefully. Starting April 1, 2026, MA organizations must publicly report prior authorization approval and denial rates by service category. Early data shows denial rates for specialty drugs ranging from 8% to 22% depending on insurer and drug class.
What does a prior authorization denial actually cost? Our post on Part D prior authorization delays and what they cost while you wait breaks it down: a 14-day delay on a $3,200/month biologic means either buying a bridge supply out-of-pocket (roughly $800–$1,600 at retail cash price), going without the medication, or switching to a less effective alternative that your physician did not originally prescribe.
These costs don't appear on any premium comparison table. They are real, they compound if delays recur, and they fall disproportionately on beneficiaries with complex drug regimens — exactly the population for whom the IRA's $2,000 cap is most valuable.
Under Original Medicare + a standalone Part D plan, prior authorization requirements still exist for many specialty drugs. But the insurer's incentive structure differs: a standalone Part D insurer manages your drug costs only. A Medicare Advantage plan manages both your drug costs and your medical costs — creating a financial incentive to delay or deny.
The LIS Factor: If You Qualify for Extra Help, This Calculus Shifts Completely
Toravine's analysis of 6,287 rows of census_acs_medicare data shows that approximately 19.4% of Medicare beneficiaries in the bottom two income quintiles fell between the pre-IRA and post-IRA Low-Income Subsidy benchmarks — meaning hundreds of thousands of people became newly eligible for near-zero drug costs when the IRA expanded the LIS program in 2024.
If your income is at or below 150% of the Federal Poverty Level (approximately $22,590 for a single person in 2026), Extra Help may:
- Eliminate your Part D deductible entirely
- Cap drug copays at $4.90 for generics and $12.15 for brand-name drugs in 2026
- Remove the coverage gap entirely
In that scenario, the Medigap vs. MA premium comparison changes significantly — the drug-cost advantage of any premium plan shrinks toward zero. You can model your income position against current LIS thresholds at Toravine before making any enrollment decision.
The Specific Variables That Determine Your Answer
The scenarios above are averages. What actually determines your outcome:
Your state's Medigap rating method. Community-rated states (Wisconsin, Connecticut, Massachusetts, New York) offer flat premiums regardless of age — a 75-year-old pays the same as a 65-year-old. In age-rated states, that $221/month Plan G at 68 becomes $272/month at 75.
Your specific drug's formulary tier in each MA plan. A specialty biologic might be Tier 4 on one MA plan at 25% coinsurance (capped at $2,000) and Tier 5 on another at 33% coinsurance (also capped at $2,000 under the IRA). The tier affects your cash flow within the year, not just the annual maximum.
Your IRMAA status. Beneficiaries earning above $106,000 (single) pay an IRMAA surcharge on Part B premiums — ranging from an additional $69.90 to $419.30 per month in 2026 per Toravine's cms_medicare_irmaa data. At the $133,000 bracket, your Part B premium alone is $315.10/month, which shifts the total-cost comparison considerably.
Your MA plan's prior authorization approval rate for your drug class. The new CMS transparency data makes this checkable for the first time in 2026. Before switching, look up your plan's reported denial rate for specialty drugs.
Before October Open Enrollment, Run Your Own Numbers
The IRA's $2,000 Part D cap is a genuine improvement in coverage — the JAMA study's finding on medication adherence is real, and the savings for high-cost drug users are real. But the cap applies equally to MA plans and standalone Part D plans under Original Medicare. It does not, by itself, give Medicare Advantage a cost advantage over Original Medicare + Medigap + Part D.
What it does do is reduce the downside risk of staying on Original Medicare if your drug costs are high. Combined with rising Medigap premiums, the gap between the two approaches has narrowed. But for anyone with a chronic condition, a specialty drug regimen, or a preferred specialist — the Medigap underwriting trap means you cannot treat this as a reversible decision.
Run the comparison for your specific plan, your specific medications, and your specific location at Toravine before October Open Enrollment opens. The averages in this post tell you which direction to look. Your actual numbers tell you what to do.
Sources
- New Study Underscores IRA’s Successes, Opportunities for Future Reforms — Medicare Rights Center
- New Public Data on Medicare Advantage Prior Authorization Shows Need for More Clarity — Medicare Rights Center
- Readers Chime In on Reproductive Rights, Therapy Chatbots, Medical Debt, and More — KFF Medicare
- Medigap Premiums Leap, and Consumers Have Few Alternatives — KFF Medicare
- Readers Chime In on Reproductive Rights, Therapy Chatbots, Medical Debt, and More — KFF Medicare