Long-Term Treatment of Hypogonadal Men with Testosterone Produces Substantial and Sustained Weight Loss

Objective: This study analyzed the effects of normalization of serum testosterone (T) levels on anthropometric parameters in hypogonadal men. Design and Methods: Open-label, single-center, cumulative, prospective registry study of 255 men (aged 33-69 years, mean 58.02 +/- 6.30 years), with T levels below 12.13 nmol/L (mean: 9.93 +/- 1.38). 215 men for at least 2 years, 182 for 3 years, 148 for 4, and 116 for at least 5 years were studied. They received parenteral T undecanoate 1,000 mg/12 weeks after an initial interval of 6 weeks. Results: Body weight (BW) decreased from 106.22 +/- 16.93 kg to 90.07 +/- 9.51 kg. Waist circumference (WC) reduced from 107.24 +/- 9.14 cm to 98.46 +/- 7.39 cm. BMI (m/kg(2)) declined from 33.9 +/- 5.51 m/kg 2 to 29.13 +/- 3.09 m/kg(2). All parameters examined were statistically significant with P < 0.0001 versus baseline and versus the previous year over 5 years indicating a continuous weight loss over the full observation period. The mean per cent weight loss after 1 year was 4.16 +/- 0.31%, after 2 years 7.54 +/- 0.32%, after 3 years 9.23 +/- 0.33%, after 4 years 11.42 +/- 0.35% and after 5 years 13.57 +/- 0.37%. Conclusions: In an uncontrolled, observational cohort, normalizing serum T to normal physiological levels produced consistent loss of BW, WC, and BMI. These improvements were progressive over the full 5 years of the study.