Yes, you can deduct medical insurance premiums paid after tax (rather than pre tax as a payroll deduction) if you itemize and the total expenses for you, your spouse, and your dependents exceed 10% of your adjusted gross income (7.5% if you're 65 or older as of December 31, 2016).
The deduction is limited to the expenses above and beyond this amount.
To enter your medical /insurance expenses -
- Click on Federal Taxes (Personal using Home and Business)
- Click on Deductions and Credits
- Click on I'll choose what I work on (if shown)
- Scroll down to Medical
- On Medical Expenses, click the start or update button
See How much did you spend on insurance premiums? page.