I was on Synthroid for 1.5 yrs, it caused me sleeplesness, dry skin, continually chapped lips, and made mt hair so dry and brittle it was falling out (Lost most of it on my head). I kept telling my doc for a year but he said the drug didn't have any side effects, it was the condition. Finally he increased the dosage a little from .1mg to .125mg, that made things much worse! I stopped taking the Synthroid and those symptoms went away, my hair grew back. I got rid of that doc, the next one sent me to an endochronoligist who did a sonogram and said my thyroid was atrophied (smaller then it should be), I told him about the synthroid so he put me on Armour and Levothyroxine which worked well. My company recently changed prescrip carriers, they sent me Synthroid and the symptoms returned, not quite as bad at only .025mg but still enough for me to say Synthroid sucks! If you are having side effects insist that your doc listen and change meds!