while receiving social security benefits in 2025 I also was paying monthly for a supplemental (part c) are the premiums tax deductible?

[DavidD66]

Medicare premiums, including supplemental coverage are potentially tax deductible as medical expenses.  In order to receive a deduction, you must itemize deductions (as opposed to taking the standard deduction).  In addition, only the amount of medical expenses that exceed 7.5% of your Adjusted Gross Income are deductible. 

[rjs]

It's not clear what you paid for. Medicare supplemental insurance (also called Medigap) and Medicare Part C (also called Medicare Advantage) are two different kinds of insurance. But either way, if you paid the premiums directly and were not reimbursed, the premiums are deductible as a medical expense.

Since medical expenses are an itemized deduction, they will not reduce your tax or increase your refund unless your total itemized deductions are more than your standard deduction.

In TurboTax, enter the full amount that you paid. TurboTax will subtract 7.5% of your Adjusted Gross Income (AGI).