Abstract: To normalize the thyroid status in hypothyroidism caused by resistance to thyroid-stimulating hormone (TSH), low-molecular-weight allosteric agonists of TSH receptor can be used. A new compound ethyl-2-(4-(4-(5-amino-6-(tert-butylcarbamoyl)-2-(methylthio)thieno[2,3-d]-pyrimidine-4-yl)phenyl)-1H-1,2,3-triazol-1-yl) acetate (TPY3m), which stimulated the production of thyroxine when administered to rats (25 mg/kg, i.p.) and also increased the expression of thyroidogenic genes in the cultured FRTL-5 thyrocytes (30 μM) and the rat thyroid gland. The in vitro and in vivo treatment with TPY3m did not lead to a decrease in the expression of the TSH receptor gene in thyrocytes, restoring it under the conditions of receptor hyperactivation by the hormone. This determines the retaining and, in some cases, potentiation of the thyroidogenic effects of TSH (FRTL-5) or thyroliberin (rats) when they are coadministered with TPY3m. TPY3m is a prototype drug for correcting thyroid system functions in subclinical hypothyroidism.