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.
