You will find some say yes, some say no. Me,personally - I do not take my meds before. It won't affect your TSH, but can raise your total thryoxine and your free T4 by up to 20% for 1 - 4 hrs after you take your dose. I schedule for first thing in the morning, fasting, take my synthroid after my blood is drawn, and then wait an hour before eating. More important - consistency. Once you decide how you are going to do it, stick to the same method for all future tests. Hope that helped excellent site Thyroid Manager