As a self employed person, your medicare premiums qualify for the "Self-employed health insurance deduction" on line 16 of Schedule 1 (technically an adjustment to income).
You may not take a deduction (for medicare or other health insurance for you or your family) directly on Schedule C (business income and expenses). That is, it is still a personal deduction, not a business deduction. It cannot reduce you net profit for purposes of the Self Employment Tax.
