Testosterone treatment may improve body composition, glucose metabolism, and sexual desire in some older men at high risk of type 2 diabetes when combined with a lifestyle program, according to research presented on June 14 at ENDO 2026, the Endocrine Society's annual meeting in Chicago.
The findings are based on a sub-study of the Testosterone for the Prevention of Type 2 Diabetes Mellitus (T4DM) trial published in 2021. The original study involved 1,007 men aged 50-74 who were either at high risk for or had newly diagnosed type 2 diabetes. The new research focused on a subset of 121 participants who continued blinded treatment for an additional two years after the initial study period but did not continue enrollment in the lifestyle program.
Researchers aimed to determine the longer-term effects of testosterone treatment on blood sugar control, obesity measures, skeletal muscle mass and strength, sexual function, and safety. Results indicated that most benefits related to blood sugar control occurred during the first two years and lessened by year four. However, blood sugar control remained significantly better than placebo over four years. Improvements in body composition—specifically reductions in fat and increases in muscle—and sexual desire observed during the first two years were maintained through year four.
The study found no clear improvement in overall quality of life compared with placebo at either two or four years; both groups reported similar quality-of-life outcomes throughout the study duration. No new safety concerns emerged during this extended observation period.
"Our data found that in the specific group of men 50 and older we studied, testosterone alone is not a replacement for changes in diet and exercise, and that it is most beneficial when paired with a lifestyle program. It also may encourage clinicians to look more carefully at men's metabolic health, waist circumference, muscle health, sexual symptoms, and testosterone status as connected issues rather than treating them in isolation," Wittert explained.
