Subnormal levels of testosterone are associated with significant negative health consequences, with higher risks of all-cause and cardiovascular mortality. The numbers of studies reporting on the benefits of normalisation of testosterone is increasing but longer-term data on (elderly) men receiving testosterone treatment are almost nonexistent. In this single-centre, cumulative, prospective, registry study, 115 hypogonadal men (mean age 59.05 years) received injections with testosterone undecanoate in 12-week intervals for up to 10 years. Waist circumference, body weight and mean BMI dropped progressively with statistical significance versus previous year for 7 years and, respectively, 8 years for weight and body mass index. Similarly, fasting glucose displayed a significant decrease after the first year continuing to decrease thereafter. A decline in HbA1c, from 6.4% to 5.6% (mean <6%), was observed from year 2 on, together with a decrease in the ratio of triglycerides:high-density lipoprotein (HDL), a surrogate marker of insulin resistance, with an increase in HDL levels. The total cholesterol:HDL ratio and non-HDL cholesterol declined significantly. A decrease was also observed in systolic and diastolic blood pressure, with a decrease in levels of the inflammation marker C-reactive protein. No major adverse cardiovascular events were observed throughout the study.