Could GLP1-based weight management medications help sperm quality?

Some men with elevated weight struggle with infertility. Obesity can lead to central hypogonadism, which means that secretion of brain hormones that normally control testicular function (LH and FSH) are dampened, which can lead to low testosterone levels and/or impaired sperm production. Excess fat tissue in men leading to increased conversion of testosterone to estrogen, insulin resistance, and chronic inflammation in men with obesity contribute to this problem, which can lead to low testosterone levels and negatively impacted sperm health. With weight loss, central hypogonadism can improve, increasing testosterone production and improving testicular function and sperm health.

So it’s a natural question to ask: Given the weight and metabolic benefits of GLP1 receptor agonists, could GLP1 based weight management medications like liraglutide (Saxenda), semaglutide (Wegovy), or tirzepatide (Mounjaro/Zepbound) improve male reproductive health?

GLP1 receptor agonist medication may actually be helpful for male reproductive health, as summarized in this review. Small studies have suggested that GLP1’s may enhance sperm count, concentration, metabolism and motility, and increase testosterone levels. Not only may weight loss be at play here, but the reduction in inflammation and insulin resistance may be at play here as well. There are GLP1 receptors on testicular (Sertoli and Leydig) cell, which seem to play a role in testicular metabolism and energy homeostasis. Most of the very small studies are with liraglutide; it would be interesting to know if the more highly effective medications like semaglutide or tirzepatide could be more beneficial.

We don’t yet know if these improvements in sperm parameters translate to improved pregnancy and birth rates, as studies haven’t yet looked at this.

Could there be any reproductive safety concerns with GLP1 use in men seeking fertility? While there have been no identified concerns, it’s a particularly important question, given the millions of people using these medications, and the great interest in the male infertility and assisted reproduction/IVF fields to consider GLP1-based medication as preconception treatment for men.

Note: For women, as we do not want women of any body size losing weight in pregnancy, GLP1 based weight management medications like liraglutide (Saxenda), semaglutide (Wegovy), tirzepatide (Mounjaro/Zepbound) have not been studied in pregnancy. They must not be used while pregnant or breastfeeding, and they must also be stopped before pregnancy attempts, as there are no safety data to tell us about any potential impact of GLP1-based medication on the developing egg.

BOTTOM LINE: Very preliminary data suggests that GLP1-based medication can help improve testosterone levels and sperm parameters. Whether this translates to increased pregnancy or birth rates hasn’t been studied. There is a huge gap of knowledge regarding weight management medication, testosterone production, erectile dysfunction, and fertility that needs to be studied.

Disclaimer: I am/have been an investigator in clinical trials of liraglutide, semaglutide, and tirzepatide. I receive honoraria as a continuing medical education speaker and consultant from the makers of liraglutide and semaglutide (Novo Nordisk) and tirzepatide (Eli Lilly).

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