This is a good question to post on the thyrooid patient-to-doctor forum on this website (for Dr. Lupo). FYI, when I started synthroid for hashi, hypo in April I would feel a little weird about 30 min. after taking it. After I few weeks I adjusted, no more "side effects". Also, I could not take the generic (levothyroxine) at all!!!! I would get warm, burning, flushing skin, headache, diarrhea, mild nausae every time I took it.