Overview
- Researchers presented a systematic review at ENDO 2026 on June 15 that pooled five small randomized trials and reported that GLP‑1 medications often increased or stabilized testosterone and in some studies improved sperm measures in men with high body mass index.
- An independent electronic health record analysis presented at the American Urological Association found roughly a 30% rise in testosterone after GLP‑1 or GLP‑1/GIP treatment in more than 1,600 men, supporting the trial signals but not proving cause and effect.
- Results vary by drug and study: liraglutide was linked to rises in testosterone and related hormones, semaglutide to better sperm morphology in one 24‑week trial, and dulaglutide showed no change in reproductive measures.
- Experts say the likely mechanism is indirect: weight loss and improved metabolic health reduce inflammation and hormone disruption that suppresses testicular function, which differs from direct testosterone replacement that can lower sperm production.
- Clinicians and researchers urge caution because the evidence is limited by small sample sizes, short follow‑up, and heterogeneous endpoints, and they call for larger, longer randomized trials and formal fertility evaluations before changing treatment practice.