Hello Doctor, My doctor says I have Hypothyroidism and I have to take to take Synthroid .037mcg for the rest of my life. I am a 63 year old female and my T4 levels over the last 2.5 years were 8.34, 6.32, 5.75, 6.03 and just recently in August 2016, it was 5.75. She says the level should be less than 5.5. Please tell me what is the normal range that the T4 should be, and why would I need to take it for the rest of my life if I am close to 5.5 already? Is there not a natural medication that is not a synthetic as I am afraid of the long term effects. Thank you very much! Rosemary