Testosterone Replacement Therapy Associated with Long-term Weight Loss in Obese Patients

Findings from a pair of ongoing studies into the effects of testosterone replacement therapy indicate unexpected significant improvements for obese patients.

Early data from two active studies on the effect of testosterone injections in obese patients with hypogonadism suggest that treatment may be associated with significant weight loss.

Researchers, who presented their findings at the recent European Congress of Endocrinology, have been following the treatment of 561 men with hypogonadism (as measured both by actual testosterone levels and the symptoms of low testosterone) who have been receiving testosterone injections three times a month for up to six years.

At baseline, only 5% of the men (who had a mean age just under 60) met healthy weight guidelines. Another 25% were overweight, and most of the rest were obese.

All the overweight and obese men have lost weight during the course of the study, but those who started off the fattest have lost the most. Indeed, men in the highest obesity category, grade III (BMI ≥ 40 kg/m2), had a mean weight loss of 26 kg and a reduction of waist size by 12 cm. Men in the grade II obesity category lost an average of 20 kg.

Moreover, blood pressure, lipid profile, blood sugar and every other measure of metabolic syndrome has improved throughout the trial.

Again, the benefits were highest for the most obese men. Among them, systolic blood pressure (mmHg) decreased from 161.04±14.3 to 142.05±9.57, diastolic blood pressure from 97.07±10.91 to 80.89±6.76. Total cholesterol (mg/dl) decreased from 306.76±43.03 to 192.23±9.17. HDL (mg/dl) increased from 62.76±18.7 to 72.55±13.34 (P<0.0001).

Mean fasting glucose (mg/dl) for the most obese patients decreased from 115.48±23.85 to 96.54±2.9 (P<0.0001), while HbA1c (%) fell from 7.57±1.38 to 6.08±0.5. In a subgroup of 156 men with type 2 diabetes, researchers have found a consistent improvement in their conditions.

These findings would seem to contradict a recent Australian study of men with low testosterone and diabetes. While that study did find that testosterone therapy reduced patient weight, it found no improvement in glucose metabolism. When treated men were compared to the placebo group, the mean adjusted difference for homeostatic model assessment insulin resistance was −0.08 [95% CI -0.31 to 0.47; P = 0.23].

Other studies, of course, have shown that testosterone therapy lowers weight and improves measures such as blood pressure, but researchers who presented the study said they were surprised by the fact that every single overweight man lost weight, by the fact that they lost so much weight, and by the fact that the weight loss has continued for the duration of the study with no indication of people regaining weight.

“These findings are important because obesity grade III is commonly considered a potential indication for obesity (bariatric) surgery; as is grade II in the presence of type 2 diabetes,” said the study’s lead investigator, Farid Saad, MD, a professor at the Gulf Medical University’s School of Medicine in Ajman, United Arab Emirates.

Other members of the study team came from Boston University and various institutions in Germany. The patients in the study were German.

“Thus,” continued Saad, who also works for the Bayer, “testosterone therapy could be considered an alternative to obesity surgery in these men.”