From the article:
The current study included 94 men with Type 2 diabetes. Prior to being treated, the 44 men in the study with low testosterone levels expressed significantly lower levels of insulin signaling genes and, thus, diminished insulin sensitivity. These men were randomized to receive a testosterone injection or a placebo every week for 24 weeks.
The study found that while there was no change in body weight, testosterone treatment produced a reduction in total body fat of 3 kilograms (more than six pounds) while increasing muscle mass by the same amount.
“Most importantly, we saw a dramatic increase in insulin sensitivity, demonstrated by a 32 percent increase in the uptake of glucose by tissues in response to insulin,” Dandona said. At the same time, there was a similar increase in the expression of the major genes that mediate insulin signaling.
While patients' hemoglobin A1C (HbA1c) levels did not go down, a necessary indicator that testosterone can help control diabetes, Dandona noted that fasting glucose levels had diminished significantly, by 12 milligrams per deciliter. He said that a significant improvement in HbA1c may eventually be seen when longer term studies are carried out.