The pharmaceutical company Bayer and Gulf Medical University in the United Arab Emirates led the research, using 11 years’ worth of data.
The researchers collected data since 2004 of 471 men with functional hypogonadism, or low testosterone production, and obesity from a German urological practice.
Around 58% of the men received an injection of testosterone every 3 months for the duration of the study, while the remainder chose not to have the treatment and therefore acted as controls. The average age of the participants was 61.57.
Medical staff administered and documented all injections at a doctor’s office, which assures that all participants received the treatment in a consistent manner. No participants dropped out of the study.
The men who received testosterone lost on average 23 kilograms (kg) (equivalent to 20% body weight) during the study period, while those who did not receive treatment gained an average of 6 kg.
Body mass index (BMI) correspondingly decreased by an average of 7.6 points in those who received testosterone therapy, compared with an increase of 2 points in the control group.
Waist circumference, which is a risk factor for cardiometabolic disease, decreased by an average of 13 centimeters (cm) in the treatment group, compared with a 7 cm increase in the control group.
The testosterone-treated men also had less internal (visceral) fat by the end of the study period. They may have had a lower risk of cardiovascular disease than those who did not receive treatment.
Overall, 28% of men in the control group had a heart attack, and 27.2% had a stroke during the study period. There were no major cardiovascular events in the men who received testosterone therapy.
Likewise, while more than 20% of the control group developed type 2 diabetes during the study period, nobody in the treatment group developed the condition.
Commenting on the results, Farid Saad of Bayer said: “Long-term testosterone therapy in hypogonadal men resulted in profound and sustained […] weight loss, which may have contributed to reductions in mortality and cardiovascular events.”