I have been on Synthroid for many, many years. Last summer, due to severe temperature fluctuations, I finally had a CT scan and found out that I have NO thyroid gland! Doc thinks Hashimoto auto immune syndrome destroyed it over the years. I have been doing ok on 75 mcg Synthroid, but having lots of BOTH hot and cold temperature fluctuations. My TSH is normal, T4 normal, but T3 very low. Doc said she would give me Cytomel, but that it would make the hot flashes worse. I understand being "cold" with low T3, but to not understand the "hot" flashes (am way over menopause age). Just wondering if anybody else has both both and cold flashes with low T3. Thank you and the best of health to you all.