Updated for 2019 :
You do get to take off the 50% ER portion of the SE tax as an adjustment on 1040 Schedule 1 line 14. The SE tax is already included in your tax due or reduced your refund. It is on the 1040 Schedule 2 line 4 which goes to 1040 line 15. The SE tax is in addition to your regular income tax on the net profit.
