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PlainMedicare

Is Prosol (alanine and 16 more ingredients) covered by Medicare Part D?

3,806 of 5,052 Medicare Part D plan offerings (75.3%) list Prosol on their 2026 formulary, most often on tier 4; 98.8% of the formularies that cover it require prior authorization. Part D spending on it was $17 million in 2024 for 4,524 people: what plans and patients paid at the pharmacy, before manufacturer rebates (CMS Part D Spending by Drug).

Plans that cover it
75.3%
3,806 of 5,052 offerings; the median drug: 76%
Usual tier
Tier 4
from tier 1 to tier 6
Prior authorization
98.8%
of formularies that cover it; the median drug: 1%
Quantity limits
0%
of formularies that cover it; the median drug: 30%

Source: CMS Part D formulary file, 2026 second quarter: the formularies in use in 2026. A plan's 2027 formulary can differ; check your own plan's coverage in Medicare Plan Finder.

What does it cost under Part D in 2027?

Your yearly cap in 2027
Out-of-pocket spending on covered Part D drugs stops at $2,400 in 2027 ($2,100 in 2026); after that, you pay nothing for covered drugs for the rest of the year.
The deductible
A plan's drug deductible is at most $700 in 2027 ($615 in 2026); many plans charge less or none.

Source: CMS, Announcement of calendar year 2027 Part D parameters; Medicare.gov, “How much does Medicare drug coverage cost?” (read Oct. 7, 2026).

How much does Medicare spend on it?

Part D spending by year

2020$28 million
2021$21 million
2022$19 million
2023$16 million
2024 (latest)$17 million

4,524 people filled it under Part D in 2024, in 99,138 claims. The amounts are what plans and patients paid at the pharmacy, before manufacturer rebates.

Source: CMS Medicare Part D Spending by Drug, 2020 to 2024 (published June 2026). Row used: Prosol (Parenteral Amino Acid 20% No.1).

Which forms and strengths are counted?

  • alanine 27.6 mg/ml / arginine 19.6 mg/ml / aspartate 6 mg/ml / glutamate 10.2 mg/ml / glycine 20.6 mg/ml / histidine 11.8 mg/ml / isoleucine 10.8 mg/ml / leucine 10.8 mg/ml / lysine 13.5 mg/ml / methionine 7.6 mg/ml / phenylalanine 10 mg/ml / proline 13.4 mg/ml / serine 10.2 mg/ml / threonine 9.8 mg/ml / tryptophan 3.2 mg/ml / tyrosine 0.5 mg/ml / valine 14.4 mg/ml injectable solution

Which other versions are listed?

The same ingredients under other names, each with its own coverage and spending.

What else should you check?

Data, not medical advice. Coverage is the share of plan formularies listing the drug; your plan's formulary, tier and pharmacy decide what you pay.