This article has tested the stability in use of T3-sulphate rather than T3 alone for combination therapy. The T3-sulphate gives a much more even response than T3 only, and lowers the "spiking" seen shortly after taking.
CLINICAL TRIAL ARTICLE
Front. Endocrinol., 29 November 2019 | doi.org/10.3389/fendo.2019....
Treatment of Hypothyroid Patients With L-Thyroxine (L-T4) Plus Triiodothyronine Sulfate (T3S). A Phase II, Open-Label, Single Center, Parallel Groups Study on Therapeutic Efficacy and Tolerability
Ferruccio Santini, Giovanni Ceccarini, Caterina Pelosini, Monica Giannetti, Ilaria Ricco, Giorgia Querci, Enzo Grossi, Giorgio Saponati and Paolo Vitti