Testosterone and the prevention of type 2 diabetes mellitus: Therapeutic implications from recent trials

Purpose of review Type 2 diabetes (T2D) is increasing to epidemic proportions and frequently associated with obesity and a low serum testosterone concentration in men. This review valuates recent randomized controlled trials (RCTs) investigating the effect of testosterone treatment on glycemic control and T2D prevention. Recent findings The 2-year Testosterone for the Prevention of Type 2 diabetes Trial (T4DM) study showed that in men aged 50 years and over with visceral obesity and impaired glucose tolerance, testosterone treatment on the background of a lifestyle intervention reduced T2D risk by 40%. The Testosterone Effects on Atherosclerosis Progression in Aging Men and Testosterone Trials demonstrated modest improvements in insulin sensitivity and body composition. However, the Testosterone Replacement Therapy for Assessment of Long-Term Vascular Events and Efficacy Response in Hypogonadal Men trial found no significant glycemic benefits over 2 years. Recent data from the Diabetes Prevention Program Outcome Study support the cost efficacy and durability of metformin. Summary In men at high risk of T2D, treatment with testosterone prevents the disease; however, there are caveats to its use and other approaches may be more applicable. Differences in trial designs, age groups, and outcome measures contribute to varying results. HbA1C is a suboptimal outcome measure. Future research should explore potential synergies between testosterone and GLP-1 receptor agonists in T2D management, while considering cost-effectiveness.