Newer generations of obesity drugs may offer an additional benefit: improving male fertility. A systematic review presented at the Endocrine Society’s annual meeting suggests that medications targeting the GLP-1 pathway could potentially increase testosterone levels and enhance sperm quality in men struggling with obesity.
While the evidence is considered preliminary and requires further confirmation through more robust trials, Pratibha Natesh, a co-author of the review and an endocrinologist at Warwick Medical School in the UK, noted that other emerging data supports this direction.
Examining GLP-1 Medications and Male Fertility
Many contemporary obesity drugs function by interacting with the glucagon-like peptide 1 (GLP-1) receptor, a natural hormone that signals fullness. Natesh and her colleagues investigated the impact of these drugs on male fertility by searching for randomized controlled trials that measured testosterone levels in men receiving GLP-1 medications. Their search identified five relevant studies.
One study involved 30 men diagnosed with both obesity and hypogonadism, a condition characterized by low testosterone levels. Participants were randomly assigned to receive either a GLP-1 drug or testosterone replacement therapy (TRT). After 16 weeks, both groups showed an increase in testosterone levels.
Another study assigned 25 men with type 2 diabetes and hypogonadism to either a GLP-1 drug or TRT. Over 24 weeks, testosterone levels rose in both groups, with a more significant increase observed in the TRT group. However, the GLP-1 group experienced improvements in sperm quality. Specifically, the proportion of morphologically normal sperm, meaning those with ideal shape and size, increased from 2% to 4% by the study’s conclusion. In contrast, the TRT group saw a decline in sperm count and quality, which is an expected outcome of that therapy.
The remaining three studies included in the review involved healthy men who took GLP-1 medications for short durations. These studies found no impact on testosterone levels.
Supporting Evidence for Testosterone Increase
The findings from the systematic review are corroborated by other research. For instance, a study presented at the American Urological Association annual meeting analyzed electronic health records of over 1,600 men prescribed obesity drugs. Researchers found that participants’ testosterone levels increased by approximately 30% after treatment with either a GLP-1 drug or a dual-acting drug that mimics both GLP-1 and glucose-dependent insulinotropic polypeptide (GIP).
Helene Elliott is the senior reporter for News Raise. She covers Science news. She also has a keen interest in photojournalism. Helene holds a nomination for the prestigious Red Smith Award. She is married to author Dennis D’Agostino, a former publicist with the New York Mets.
