ENDO 2026 reviews find GLP-1 drugs do not harm male fertility and may improve testosterone

Two reviews presented at ENDO 2026, the Endocrine Society's annual meeting in Chicago, found no evidence that GLP-1 medications harm male hormones or fertility, and some signs the drugs may improve testosterone and sperm quality in men whose weight and metabolic health are the underlying problem ^[1][2].

The conference review came from researchers at University Hospitals Coventry and Warwickshire and Warwick Medical School in Coventry, United Kingdom. They searched medical databases for published randomized controlled trials that compared GLP-1 drugs with placebo or another treatment in men aged 18 to 65. Two independent reviewers screened the studies to reduce bias, and five trials met the eligibility criteria ^[1].

Those trials reported no negative effect on hormones, sexual function or sperm quality. In one, 24 weeks of semaglutide was linked to improvements in sperm shape and cholesterol levels, while testosterone and other hormone levels stayed stable ^[1]. In another, 16 weeks of liraglutide in men with obesity and low testosterone raised testosterone and related hormones. Their overall health outcomes were better than with testosterone replacement alone ^[1].

A second review, published in the journal Urology in its July 2026 issue (volume 213, pages 9 to 17), searched PubMed, MEDLINE and Embase through May 31, 2025, and identified 16 clinical studies ^[2]. It reports that GLP-1 receptors are found in male reproductive tissues, that rodent studies of obesity and diabetes showed better sperm production, hormone profiles and sperm function, and that laboratory work showed improved sperm motility ^[2]. The same review gives specific numbers from a 2025 randomized trial: after 24 weeks of once-weekly semaglutide 1 mg in men with obesity, type 2 diabetes and hypogonadism, normal sperm morphology rose from 2 percent to 4 percent, which the authors called significant (P = .012) ^[2]. The review still describes the human evidence as limited, with results that vary from study to study ^[2].

“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,” said Pratibha Natesh, M.B.B.S., M.R.C.P., M.Res., the endocrinologist at Warwick Medical School who led the team ^[1].

Natesh also cautioned that the number of studies is small and their results vary, so larger and better-designed studies are needed. She said most of the reproductive benefits seen are likely indirect, and that GLP-1s have not been evaluated as treatments for male infertility or hypogonadism ^[1]. The Urology review reaches a similar conclusion: GLP-1 drugs likely help male fertility, especially when metabolic dysfunction is present, but the clinical evidence is limited and larger prospective studies are needed to confirm safety and effectiveness ^[2].

The two reviews also differ in scope. The conference review counted five randomized trials; the Urology review counted 16 clinical studies, using different inclusion criteria ^[1][2]. And one study listed among the Urology review's references points the other way on a related question: a database analysis reported that semaglutide prescribed for weight loss in non-diabetic men with obesity was associated with an increased risk of erectile dysfunction ^[2]. That sits uneasily with the conference review's conclusion of no negative effect on sexual function ^[1].

Why it matters for patients

Obesity-related low testosterone is common in men, and GLP-1 drugs are now widely prescribed for weight loss and diabetes. A central question for men of reproductive age has been whether these drugs help or hurt fertility.

The studies reviewed here found no harm signal for hormones or sperm, and some improvement in men whose weight and metabolic health were the problem. But the evidence base is small, and the results are not uniform. Neither review identifies GLP-1 drugs as a treatment for male infertility or hypogonadism, and neither says these drugs should replace or add to testosterone therapy for that purpose. Whether the improvements came from the drugs themselves or mainly from weight loss and better metabolic health has not been settled; the conference team says most of the benefit is likely indirect ^[1].

Cost, insurance coverage for fertility-related use, and effects in men who do not have obesity are not addressed in either review.

What happens next

The Urology review appears in the July 2026 issue of the journal ^[2]. Both teams call for larger, better-designed studies in men, including prospective trials that measure semen parameters and hormones directly ^[1][2]. No specific new trials, funding or timelines have been announced in either review.