If your S-corp paid your health insurance premiums, you should include this total (annual) amount in Box 1 of your W-2 (but not Boxes 3 or 5). That will record the health insurance as a deductible compensation expense for your S-corp on its Form 1120S (and as taxable wage income to you, on your personal Form 1040 tax return). You will then be further eligible to take a self-employed health insurance deduction on your Form 1040 . . . thus eliminating the extra taxation to you individually, that was created by reporting the extra W-2 Box 1 wage income.
For more information on this, as well as a formal discussion, please refer to the following IRS.gov webpage:
https://www.irs.gov/businesses/small-businesses-self-employed/s-corporation-compensation-and-medical...
In particular, you may find the sections titled "Treating Medical Insurance Premiums as Wages" and "Health Insurance Purchased in Name of Shareholder" especially relevant.
For mechanical instructions on how to take the self-employed health insurance deduction for 2% + S-corp shareholders in TurboTax, you can refer to the details and steps found here:
https://ttlc.intuit.com/questions/2966948-s-corp-self-employed-health-insurance-deduction
Thank you for asking this important question.
