Health insurance "premiums" are tax deductible if you have a net profit on a schedule C.
Your personal health insurance cannot be written off directly on your schedule C.
You are also eligible for a deduction if you are a general partner, a limited partner who receives guaranteed payments, or a shareholder who owns more than 2% with wages from the S corp that are reported on the W-2.
Here is a TurboTax article about self-employed health insurance premiums:
https://turbotax.intuit.com/tax-tips/home-ownership/deducting-health-insurance-premiums-if-youre-sel...
