Thank you 'humanbean' putting this info in a reply to Zmcb13. Very interesting!
"In the UK during the first half of the 20th century many people who suffered with hypothyroidism did not get treated. A doctor wrote an article on the subject for the BMJ (British Medical Journal) in 1949, complete with pictures of people who had been suffering from extreme forms of hypothyroidism, and what happened after treatment was begun. You should read it :"
The doctor at the time used cholesterol as a measurement to help the cure of myxoedema, the extreme form of hypothyroidism. Today doc's seem to ignore the relationship between thyroid output and cholesterol amounts in the blood.
I stopped taking T3 for about 6 months (an other story) and my cholesterol levels raised to 10. After taking T3 again the cholesterol lowered to 6 but 4 or less is ideal. Could this be used as a marker for limiting the T3 dose perhaps T4 as well? GP's are usually keen if you ask for a cholesterol check.