Deductions & credits

Both comments above are correct, but let me explain a little further.

If the contributions to your HSA are through your employer (whether your employer made them or you did through payroll deduction or both), this amount is reported with code W in box 12 of your W-2.

Before the employer prints the W-2, the employer removes the code W amount from Wages in boxes 1, 3, and 5. This is why you don't see a deduction for this amount - because it was never in your income in the first place.

HSA contributions through the employer are a deferral, not a deduction - that it, taxes are deferred until some later date (and as TomYoung alludes to, if the HSA money is spent on qualified medical expenses, it is never taxed at all).

Only if you make contributions directly to the HSA (not through your employer) will a deduct appear on the return - in line 25 on Schedule 1 (Form 1040).