Ozempic and Wegovy may improve fertility in overweight men

A new systematic review by researchers from the University of Warwick's medical school shows that GLP-1 weight-loss medications such as Ozempic and Wegovy raise testosterone levels in overweight men and improve sperm quality. Unlike testosterone replacement therapy, these medications do not harm male fertility. Preliminary findings from the study were presented at the Endocrine Society's annual meeting in Chicago.

Pratibha Natesh, an endocrinologist at the University of Warwick's medical school, and her colleagues published a systematic review offering hope to overweight men who wish to have children. It turns out that popular weight-loss medications such as Ozempic and Wegovy can raise testosterone levels and improve sperm quality without damaging fertility.

Why obesity impairs fertility

Doctors have long known that excess body fat negatively affects hormonal balance in men. Fat cells contain an enzyme that converts the male sex hormone testosterone into the female sex hormone estradiol, the more adipose tissue, the more intense this process. Additionally, obesity causes chronic inflammation in the body, which strains the organism and further reduces testosterone production. Low hormone levels directly harm the development of viable sperm cells.

Until now, doctors have often treated such patients with testosterone replacement therapy, which helps preserve muscle mass and mood but creates a significant paradox: externally administered testosterone suppresses the body's own sperm production, thus reducing the number and quality of sperm cells.

Five clinical trials analysed

Natesh's team analysed five previously conducted randomised controlled trials. One of them involved 30 overweight men diagnosed with sex hormone deficiency. Half of them received GLP-1 medication over 16 weeks, while the rest received testosterone preparations. In both groups, testosterone levels rose, but in the men who received weight-loss medication, the proportion of normally shaped and sized spermatozoids increased from two per cent to four per cent. In the replacement therapy group, by contrast, both the number and quality of spermatozoids declined.

In a second trial, 25 men with type 2 diabetes and hormone deficiency were examined. Similar to the first trial, hormone levels rose in both groups over 24 weeks, although the increase was greater with replacement therapy. The remaining three trials focused on GLP-1 use in healthy men, and their testosterone levels did not change significantly, suggesting that the medication's beneficial effect appears primarily in overweight patients.

Findings supported by other studies

The conclusions drawn by the University of Warwick team are also supported by findings from other researchers. Dr. Andrés Guillén-Lozoya from the Mayo Clinic investigated health data from over 1,600 men who were prescribed obesity medications, and after the course of treatment, their testosterone levels increased by approximately 30 per cent. Another retrospective study, which analysed the medical records of 215 men, showed that men who used GLP-1 medications had testosterone levels on average 20 per cent higher after treatment than before.

New treatment recommendations require adjustment

According to Natesh, the findings should be eye-opening for all endocrinologists treating men. In her assessment, testosterone should no longer be prescribed as a first-line treatment option to overweight and hormone-deficient patients who wish to have children.

"Rather, we should treat the underlying cause, obesity," Natesh emphasised. The combination of lifestyle changes and weight-loss medications helps restore the body's natural hormone function, without compromising fertility, according to current knowledge.

The preliminary results of the study were presented at the Endocrine Society's annual meeting in Chicago in the US.