https://ttlc.intuit.com/replies/5954552
Yes, if you are self-employed and eligible for the self-employed health insurance deduction, you can include your Medicare premiums in your self-employed health insurance deduction. It's a deduction on the front page of the 1040, line 29.
If you want these premiums to be part of the self-employed health insurance deduction, do not enter your Medicare premiums when entering the information from your SSA-1099 (Social Security Benefits). When you go through the questions for your business expenses, enter those premium expenses for self-employed health insurance premiums.