According to 2016 AACE and ACE obesity guidelines, testosterone therapy (TTh) results in weight loss and reduction in waist circumference. We investigated whether these improvements could be sustained under very long-term TTh.


Of 823 men with hypogonadism from a single urology center, 474 were obese. 281 opted for TTh (T-group) and received 3-monthly injections of testosterone undecanoate (TU), 193 against TTh (CTRL). 11-year results were analyzed. Differences between groups were adjusted for age and components of the metabolic syndrome.


Mean age: T-group: 59.9±6, CTRL: 63.5±5 years, mean follow-up 8.5±2.7, median 9 years. In the T-group, weight decreased by 23.2±0.3 kg after 11 years (p<0.0001) and increased in CTRL by 4.2±0.5 kg (p<0.0001). The per cent weight reduction in the T-group was 20.6±0.3% (p<0.0001), the increase in CTRL was 5.1±0.4% (p<0.0001)In the T-group, waist circumference decreased by 12.9±0.2 cm (p<0.0001) and increased in CTRL by 5.6±0.4 cm (p<0.0001).In the T-group, BMI decreased by 7.7±0.2 kg/m² (p<0.0001) and increased in CTRL by 1.8±0.3 kg/m² (p<0.0001).In the T-group, waist:height ratio decreased by 0.07±0.0 (p<0.0001) and increased in CTRL by 0.03±0.0 (p<0.0001).Adverse events: In the T-group, 18 patients (6.4%) died of non-cardiovascular events. There were no non-fatal major adverse cardiovascular events (MACE). In CTRL, 60 patients (31.1%) died, 49 (25.4%) had a non-fatal myocardial infarction, and 50 (25.9%) had a non-fatal stroke. Incidence of prostate cancer, oftentimes a concern with TTh, was 7 (2.5%) in the T-group and 29 (15%) in CTRL (p<0.0001 for all).Medication adherence in the T-group was 100 per cent as all injections were performed in the office and documented.


Long-term treatment with TU in men with hypogonadism improved weight compared to untreated controls. Mortality and MACE but also prostate cancer incidence were higher in the control group.