In an observational study of 14 patients, no subjects developed any cardiac or skeletal disease after receiving doses from 25- to 150mcg over a two-year period.41
Note that the high dose was because they were increasing the dose based on symptoms. That is to say, as the thyroid gland produced less thyroid hormone, they increased liothyronine dose to compensate.
The substitution of l-T3 for l-T4 at equivalent doses (relative to the pituitary) reduced body weight and resulted in greater thyroid hormone action on the lipid metabolism, without detected differences in cardiovascular function or insulin sensitivity.
This implies that T4 and T3 are not identical, but I want to check the study further to see if half-life comes into play. The T3 group could theoretically have higher daily thyroidergic exposure, but maintain TSH because they experience a daily dip. Multiple dosing at least partly solves this issue. Controlled release tablets would be ideal.
At the final study visit, subjects were asked whether they thought their L-T4 doses at the end of the study were higher, lower, or unchanged from the start of the study and which of the two doses they preferred. Subjects were not able to accurately ascertain changes in L-T4 doses (P = 0.54)
The study does not provide enough information to determine whether this is meaningful. It appears to be meaningless. If they had used a crossover design, then this might be useful.
The sodium-restricted diet group received a regimen aiming a maximum intake of 3 g of sodium per day (equivalent to 7.5 g of sodium chloride).
That sounds incredibly high to me. 3000 mg is the absolute maximum intake that could ever be considered 'low' sodium. Under 1500 is usually considered ideal. Would, then, a diet aiming for half the sodium be twice as effective?
between 535 and 900 kcal, depending on age, sex, weight, and height (16).
In other words, it was isocaloric between the two groups, in that similar subjects were fed similar calories.