Hi I have just been prescribed 50 micrograms of Levothyroxine for the first time. T4 is 10.4 and TSH is 7.5. How long before I notice the difference? I want to stop shivering all the time. I am cold regardless of how many clothes I wear. My doctor says I can have another blood test in 8 weeks. This is uncharted territory for me. What can I expect?