The latest generation of weight-loss medications may offer yet another significant clinical benefit: improving reproductive function in men. According to a study presented at the Endocrine Society’s annual meeting in Chicago, these drugs increase testosterone levels and help improve sperm quality in patients. The study’s authors note that while the data are still preliminary and larger clinical trials are needed to definitively confirm the association, evidence from various sources already points to the same trend.
Scientists analyzed randomized controlled trials that measured testosterone levels in men taking GLP-1 receptor agonists. In one study, patients with obesity and hypogonadism (low testosterone) were divided into two groups: one was prescribed a GLP-1 drug, while the other received testosterone replacement therapy (TRT). After 16 weeks, hormone levels increased in both groups.
Another 24-week study showed that while the increase in hormone levels was higher in the TRT group, sperm quality significantly improved in the GLP-1 group. Specifically, the proportion of morphologically normal spermatozoa (those with correct shape and size) increased from 2% to 4%, whereas the testosterone replacement therapy group, as expected, experienced a decline in sperm count and quality.
These findings are further supported by an analysis presented by researchers from the Mayo Clinic (USA) at the American Urological Association’s annual meeting. An examination of electronic health records from more than 1,600 patients revealed that following treatment with weight-loss medications, men’s testosterone levels increased by an average of 30%. Another retrospective study of 215 patients showed an average hormone increase of 20%.
For specialists, this link comes as no surprise. It is well established that obesity directly lowers testosterone levels, which are essential for sperm production and fertility. One reason for this is that fat cells contain an enzyme that converts testosterone into estradiol (the primary female sex hormone). This is further compounded by metabolic changes and chronic inflammatory processes induced by obesity.
This discovery carries an important message for endocrinologists treating men with obesity and symptoms of low testosterone (such as reduced libido, mood changes, and loss of muscle mass), particularly those planning to conceive. The primary recommendation from physicians is that hormone therapy should not be prescribed immediately to such patients. In many cases, weight loss achieved through lifestyle modifications—and, when necessary, the introduction of weight-loss medications—is entirely sufficient to restore testosterone levels naturally, without compromising sperm quality.~
