A study presented at the Endocrine Society’s ENDO 2025 conference in San Francisco has revealed that GLP‑1 receptor agonist medications—commonly used to treat obesity and type 2 diabetes—also significantly improve testosterone levels in obese men. Researchers found that over an 18-month period, the proportion of men with normal testosterone rose from 53% to 77%, alongside notable weight loss.
The investigation was led by Dr. Shellsea Portillo Canales of SSM Health St. Louis University Hospital. Her team analyzed 110 obese men, with an average age of 54, many of whom also had type 2 diabetes. These individuals were treated with semaglutide, dulaglutide, or tirzepatide—drugs marketed under names such as Wegovy, Trulicity, Mounjaro, and Zepbound. Importantly, none of the participants had received hormone therapy before the study. The significant rise in testosterone levels was closely tied to the extent of weight loss observed across the study group.
Testosterone is essential for male sexual health and also plays a critical role in bone density, muscle mass, fat distribution, mood, energy levels, and red blood cell production. The enhancement of testosterone through GLP‑1 medications offers dual health benefits for men dealing with obesity or metabolic disorders, according to the research. Additional media coverage of the findings echoed these results, with sources noting that men not only experienced improved hormone profiles but also achieved an average of 10% reduction in body weight.
Medical experts point to several physiological mechanisms that may explain the rise in testosterone linked to GLP‑1 therapy. These include a reduction in aromatase activity within fat tissue (an enzyme that converts testosterone into estrogen), improved insulin sensitivity, lower systemic inflammation, and enhanced metabolic efficiency—all of which are known to support or restore natural testosterone production.
Of particular interest is the potential reproductive benefit of GLP‑1 drugs. A separate review presented at a reproductive health conference earlier this year found that GLP‑1 treatments such as liraglutide, semaglutide, and dulaglutide appeared to improve semen parameters. This is a significant finding, as traditional testosterone replacement therapy often negatively impacts sperm production and fertility. GLP‑1 medications, by contrast, may offer a non-hormonal option for treating functional hypogonadism—low testosterone caused by metabolic issues—without compromising reproductive health.
Although more clinical trials are needed to fully understand the long-term effects and underlying biological mechanisms, the current data are promising. With the growing popularity of GLP‑1 medications, especially among men, researchers stress the need for additional studies to explore how these drugs influence hormonal pathways and fertility outcomes over time. Further clarification is needed regarding whether GLP‑1 agonists act directly on the hypothalamic-pituitary-gonadal axis or if their benefits are purely a result of weight loss and improved metabolism.
The findings presented at ENDO 2025 represent a potential paradigm shift in how clinicians might address obesity-related hormonal imbalance in men. Rather than resorting immediately to hormone replacement therapy—which can carry side effects and fertility risks—patients may benefit from a metabolic approach that simultaneously targets weight, blood sugar, cardiovascular risk, and now, testosterone deficiency.
For now, GLP‑1 drugs are not FDA-approved to treat low testosterone, and their off-label use for this purpose should be discussed carefully with a healthcare provider. However, the emerging data suggest a compelling case for their broader consideration in men’s health strategies, especially as obesity continues to drive related endocrine disorders.