Testosterone Treatment Produces Consistent Weight Loss in Hypogonadal Men

Regulating testosterone (T) levels in men with hypogonadism for up to 5 years results in sustained reductions in body weight and waist circumference, according to a study published in Clinical Obesity.

Although previous studies had already established that T treatment reverses the fat accumulation and muscle mass reduction that characterize hypogonadism, Aksam Yassin, MD, PhD, EdD, of the Institute of Urology and Andrology at the Segeberger Kliniken hospital in Germany, and Gheorghe Doros, PhD, of the Department of Epidemiology and Statistics at Boston University’s School of Public Health, noted those trials were too short in duration to demonstrate consistent improvements. Thus, the researchers set out to determine whether long-acting T therapy sustains those effects in men with low T.

For their uncontrolled, single-site study, Yassin and Doros observed the outcomes of administering 1000 mg parenteral T undecanoate at baseline, 6 weeks, and then every 12 weeks for up to 60 months in 261 men between 32-84 years old who were seeking treatment for erectile dysfunction (ED). To track long-term anthropometric changes with T treatment, all subjects’ height, body weight, waist circumference, and body mass index (BMI) were measured at baseline and at least once a year following T injection.

At baseline, 69% of study subjects had a waist circumference of at least 102 cm, compared to 28% whose waists were between 94-101.9 cm in circumference, and 3% with a waist circumference below 94 cm. But over the 5-year observation and T treatment period, waist circumference decreased in 97.5% of the hypogonadal men — 15% of whom saw their waists slim down by more than 15 cm.

Examining changes in body weight, Yassin and Doros noticed statistically significant declines at the end of each study year compared with the previous year, as patients lost on average about 3.2% of their baseline weight after year 1, 5.6% after year 2, 7.5% after year 3, 9.1% after year 4, and 10.5% after year 5. The researchers also noticed a “consistent and progressive” reduction in BMI over the entire 60-month course of T treatment, as those measurements declined from “31.7 ± 4.4 to 30.6 ± 4.3 after 1 year, 29.9 ± 4.3 after 2 years, 29.5 ± 4.0 after 3 years, 29.4 ± 3.7 after 4 years, and 29.4 ± 3.4 after 5 years.”

Further analyzing data on the 62% of hypogonadal men who were classified as obese at the start of the study, the authors determined that “approximately 95% of the obese men lost some weight; 18% lost more than 20 kg, 40% lost more than 15 kg, 64% lost more than 10 kg, 84% lost more than 5 kg, and only 5% gained some weight,” which they said “indicated that the magnitude of changes … was more pronounced among the obese.”

Yassin and Doros wrote that the progressive reductions in body weight observed in their study were “surprising … (because) the effects of T treatment on weight was neither intended nor expected, as long-term weight loss had never before been reported in the literature as an outcome measure for T treatment.” Nevertheless, the duo used those findings to support the conclusion that “raising serum T to normal physiological levels in hypogonadal men produces consistent loss in body weight, waist circumference, and BMI.”