A recent study shows that men who have type 2 diabetes that received testosterone therapy had a 25% increase in insulin sensitivity after 24 weeks of treatment. The men analyzed had type 2 diabetes and hypogonadism (described as having a free testosterone concentration of less than 5 ng/dL), lean body mass, fat mass, sexual function, and other levels.
In total there were 81 males. Not all of the men received the testosterone therapy, half of the men were given a placebo. The men were all matched up equally.
After 24 weeks of treatment, the men who received the testosterone therapy had higher concentrations of testosterone. Meanwhile, their testicle size significantly shrunk, for example from 18 mL to 14 mL.
The moral of the story, if you have type 2 diabetes and low T, then talk to your doctor about testosterone therapy. You have a chance that your T level will rise, and your insulin resistant body may become a little less resistant.