Here is a piece of research that helps to provide another reason why T3 helps some thyroid patients struggling with blood sugar issues.
T3 appears to improve insulin sensitivity and can reduce or stop insulin resistance:
“Thyroid hormone potentiates insulin signaling and attenuates hyperglycemia and insulin resistance in a mouse model of type 2 diabetes”
Br J Pharmacol. 2011 Feb; 162(3): 597–610.
Yi Lin and Zhongjie Sun