GLP-1 trials point to possible fertility gains for men with obesity
A review presented at ENDO 2026 found no fertility harm from GLP-1 drugs and possible benefits tied to weight and metabolic health.
By Tom Brennan · Health & Medicine Correspondent
3 min read
GLP-1 weight-loss and diabetes drugs may help some men with obesity-related low testosterone without damaging sperm quality or sexual function, according to research presented Monday at ENDO 2026 in Chicago. The finding matters because testosterone treatment can affect fertility, while the reviewed trials suggest that addressing excess weight may improve reproductive hormones in some patients.
The Endocrine Society said the analysis was led by Pratibha Natesh, an endocrinologist at Warwick Medical School in the United Kingdom. Her team reviewed published randomized controlled trials involving men ages 18 to 65 that compared GLP-1 medicines with placebo or other therapies.
The researchers, from University Hospitals Coventry and Warwickshire and Warwick Medical School, searched medical databases and used two independent reviewers to screen the evidence, according to the Endocrine Society. Five clinical trials met the team’s criteria.
What the trials found
The review focused first on testosterone and other hormones involved in testicular function. The researchers also assessed sperm quality, sexual function, body weight, blood sugar, cholesterol and broader measures of metabolic health, the Endocrine Society said.
Across the eligible trials, the team reported no negative effects from GLP-1 drugs on reproductive hormones, sexual function or sperm quality. In one 24-week semaglutide trial, the Endocrine Society said researchers saw better sperm morphology and cholesterol measures while testosterone and related hormones remained stable.
A separate 16-week liraglutide trial in men with obesity and low testosterone linked to excess weight found increases in testosterone and related hormones, according to the Endocrine Society. The society said overall health results in that study were better than those seen with testosterone replacement alone.
GLP-1 receptor agonists, including semaglutide and liraglutide, are used for diabetes and weight management. The reviewed work suggests reproductive benefits may come through weight loss and improved metabolic health rather than a direct fertility effect, Natesh said.
Researchers urge caution
Natesh said the findings support treating excess weight and poor metabolic health in men with obesity-related low testosterone rather than relying first on testosterone replacement. “This work supports a shift away from prescribing testosterone replacement in men with obesity and low testosterone and toward treating the underlying cause—excess weight and poor metabolic health—which can naturally restore hormone levels and preserve fertility,” she said in a statement released by the Endocrine Society.
The researchers cautioned that the evidence base remains limited. Natesh said the number of trials was small and their results varied, so larger and better-designed studies are needed to define the drugs’ effects on male fertility.
She also said clinicians should remember that GLP-1 medicines have not been tested as treatments for male infertility or hypogonadism. Most reproductive benefits seen in the review are likely indirect, according to the Endocrine Society.
Natesh said clearer information about GLP-1 medicines may help patients weigh their options. “Improving metabolic health can have positive effects far beyond weight alone,” she said.
This story draws on original reporting from Medical Xpress.