GLP-1 weight-loss drugs may boost testosterone and sperm quality in men

GLP-1 weight-loss drugs may be doing more than shrinking waistlines. In men with obesity-related low testosterone, early studies found higher or stable testosterone and signs of better sperm quality, pointing to a possible reproductive benefit from medicines best known for Ozempic and Wegovy.

The clearest pattern comes from a January 2026 systematic review in the Journal of Sexual Medicine that pooled 10 studies and 639 men. Across those trials, GLP-1 receptor agonists were consistently associated with increased total testosterone, especially in men with obesity, type 2 diabetes or functional hypogonadism. Luteinizing hormone and follicle-stimulating hormone were preserved or increased, unlike the suppression seen with testosterone therapy comparators. The review also found semen improvements in obese or hypogonadal men, but not in healthy men.

One randomized open-label trial helps explain why the signal is attracting attention. It enrolled 25 men with type 2 diabetes, obesity and functional hypogonadism and compared semaglutide with testosterone replacement over 24 weeks. In the semaglutide group, 1 mg per week raised the share of morphologically normal sperm from 2% to 4%. In the testosterone replacement group, sperm concentration and total number fell significantly, even though total testosterone rose in both groups. That contrast matters because men who want children often cannot afford a treatment that worsens fertility while improving hormone levels.

The biology is plausible. A 2021 review in Andrology noted that human Leydig, Sertoli and germ cells express GLP-1 receptors, suggesting the drugs may act not only through weight loss but also through direct or indirect effects on the testis. A 2022 review in Frontiers in Endocrinology said up to 40% of men with obesity and/or type 2 diabetes have co-existing hypogonadism, linking reproductive problems to visceral obesity, insulin resistance and inflammation. If GLP-1 therapy improves that metabolic environment, it could help restore the hypothalamic-pituitary-gonadal axis and reduce some of the reproductive harm tied to obesity.

That is why the newest evidence is being treated as an early signal, not a finished answer. The studies are small, short-term and concentrated in men with obesity, diabetes or functional hypogonadism. For now, GLP-1 drugs should not be considered proven fertility therapy. But they may be forcing a broader rethink of a drug class that is already changing diabetes and weight-loss care, and may yet reach deeper into endocrinology and reproductive medicine than many clinicians expected.