In most cases, the premiums are pre-tax. You can't subtract (deduct) an item from your taxable income that was already subtracted from your taxable income by your employer.
In rare cases, your premiums may be partly or wholly after-tax. This is usual, and should only happen when you providing insurance for someone who is not your child, your spouse or your dependent. If part of your premiums are after-tax, that can be used as an itemized deduction.
