GLP-1 drugs can raise testosterone levels in men

The use of glucagon-like peptide 1 (GLP-1) drugs such as semaglutide, dulaglutide, and the dual agonist tirzepatide helps boost testosterone levels in men with obesity and type 2 diabetes (T2D), according to new research.

Over a mean treatment duration of 1.6 years, mean total testosterone levels significantly increased, from 322 ng/dL at baseline to 380 ng/dL (p<0.001). Similarly, mean free testosterone levels rose substantially, from 7 to 8.2 ng/dL (p=0.004). Mean sex hormone binding globulin (SHBG) slightly increased from 36 to 38 nmol/L (p=0.23). Baseline measurements were taken 0.8 years before initiation of GLP-1 therapy. [ENDO 2025, abstract RF27-03]

During the same period, mean body weight dropped significantly from 116 to 104 kg (p<0.001). Weight change showed a negative correlation with total (r=–0.30, p=0.002) and free testosterone (r=–0.28, p=0.04), but only a  trend of association was observed for SHBG.

Lead study investigator Dr Shellsea Portillo Canales from SSM Health Saint Louis University Hospital in St Louis, Missouri, US, noted that the observed increases in total and free testosterone with GLP-1 therapy were likely due to weight loss.

The study participants lost approximately 10 percent of their body weight, and this led to the normalization of testosterone levels for some, Portillo Canales said. The number of men with healthy testosterone levels (>300 ng/dL) increased from just over half (53 percent) at baseline to more than three-quarters (77 percent) at 1.6 years (p<0.001).

“While it is well known that weight loss from lifestyle changes or bariatric surgery increases testosterone levels, the impact that antiobesity medications may also have on these levels has not been widely studied,” according to Portillo Canales.

“Our study is among the first to provide compelling evidence that low testosterone can be reversed with the use of commonly prescribed antiobesity medications,” especially in cases where obesity is the underlying cause of low testosterone, she said.

“Doctors and their patients can now consider [GLP-1 drugs] not only for the treatment of obesity and to control blood sugar, but also to benefit men’s reproductive health,” she added.

For the study, Portillo Canales and colleagues analysed electronic health record data from 110 men (mean age 54 years, 80 percent White) who had a mean BMI of 35 kg/m². Those who were treated with testosterone, clomiphene, hCG, aromatase inhibitors, or androgen supplements were excluded.

Of the men, 68 percent used semaglutide, 16 percent used dulaglutide, 38 percent used tirzepatide, and 27 percent used more than one therapy.

Eighty-six men had T2D, of whom 86 percent were on oral hypoglycaemics and 21 percent used insulin. HbA1c at baseline was 7.2 percent and decreased to 6.5 percent at 1.6 years (p=0.001).