In 1926 we gave some Squibb's thyroxine for oral use to two patients with low basal metabolism for a few days in doses of from 2 to 10 mg. daily and, having observed no effect, were content to conclude that the current opinion about its lack of effect when administered by mouth was correct. However, as time went on, it seemed worth while to give the matter more serious study.
A review of the literature reveals some difference of opinion as to whether or not thyroxine is effective when administered by mouth. Swingle, Helff and Zwemer,1 by observing the weight and pulse rate, Burmeister,2 by observing the weight and urinary output, and Abelin,3 Schneider,4 and Boller and Högler5 (Schering's thyroxine), on the basis of determinations of basal metabolism, concluded that thyroxine is virtually without effect when administered by mouth to normal human beings. Weiss6 observed no effect in some cases
THOMPSON WO, THOMPSON PK, DICKIE LFN. MONOSODIUM THYROXINE, DESICCATED THYROID AND AN IMPURE SODIUM SALT OF THYROXINECOMPARISON OF THEIR EFFECTS WHEN ADMINISTERED ORALLY WITH THE EFFECT OF THYROXINE INJECTED INTRAVENOUSLY IN AN ALKALINE SOLUTION. Arch Intern Med (Chic). 1933;52(4):576–592. doi:10.1001/archinte.1933.00160040082004