Does low testosterone in men reduce insulin sensitivity and increase risk of type 2 diabetes?

For an aging male, maintaining metabolic health is closely tied to endocrine balance, as declining testosterone levels can̲ directly disrupt glycemic control.

Clinical evidence of diabetes risk and insulin resistance

• Increased Risk of Diabetes: Epidemiological and clinical data demonstrate a robust, bidirectional relationship between low testosterone (hypogonadism) and metabolic dysfunction. In men, a low total testosterone level is associated with a 1.5- to 2.1-fold increased risk of incident type 2 diabetes, whereas normal to high testosterone levels correlate with a 35% to 38% reduction in diabetes risk.
• Insulin Sensitivity and Therapeutic Reversal: Gold-standard hyperinsulinemic-euglycemic clamp studies show that hypogonadal men with type 2 diabetes have a 36% lower glucose infusion rate (GIR)—indicative of severe insulin resistance—which is improved by approximately 32% following testosterone replacement therapy (TRT). Findings from the landmark T4DM trial confirm that TRT combined with lifestyle intervention reduces progression to type 2 diabetes by roughly 40% in high-risk men.

Mechanistic pathways of metabolic dysfunction

• Impaired Skeletal Muscle Glucose Uptake: Skeletal muscle is the primary site for insulin-mediated glucose disposal. Testosterone under normal physiological conditions upregulates glucose uptake by binding to the androgen receptor, initiating rapid non-genomic activation of the PI3K-Akt, ERK, and mTOR pathways. This cascade drives the translocation of glucose transporter 4 (GLUT4) to the cell membrane. Testosterone deficiency impairs these signaling cascades and the AMPK-related metabolic network, reducing GLUT4 translocation and directly causing systemic insulin resistance.
• Promotion of Visceral Adiposity: Low testosterone drives the accumulation of visceral fat. Androgens inhibit the differentiation of multipotent stem cells into mature adipocytes by suppressing key adipogenic transcription factors (PPARγ and C/EBPα). Furthermore, testosterone deficiency increases lipoprotein lipase (LPL) activity—promoting triglyceride uptake into fat cells—and blunts lipolytic pathways. The resulting visceral adiposity releases excess free fatty acids, further worsening systemic insulin resistance.

Bottom line

• Low testosterone is a major, actionable risk factor for insulin resistance and type 2 diabetes in men. It directly impairs skeletal muscle glucose uptake by disrupting the insulin-signaling cascade and GLUT4 translocation, while simultaneously promoting visceral fat accumulation by increasing lipid storage and adipocyte differentiation.