Can Ozempic Affect Your Sperm? The Truth About GLP-1s and Male Fertility

By: Sophie Beaumont, MSc in Biochemistry candidate at Trinity College, Oxford, edited by the Jack Fertility team.

TL;DR

GLP-1 drugs like Ozempic, Wegovy, and Mounjaro are game-changers for weight loss and diabetes management, but could they also influence male fertility? While early data shows potential benefits through improved metabolic health, there’s a glaring lack of research into their direct effects on sperm.

The lack of research into GLP-1s and sperm health thus could be a Billion-Dollar blind spot in reproductive health. As more men of reproductive age turn to these medications, it’s time to ask: what do we really know?

Huge thanks to Joey Wilson, Senior Expert, Life Science Strategy at Porsche Consulting for inspiring this topic with his team's report "Weight-Loss Drugs: Booster Shots for the Market" in Porsche Consulting: The Magazine.

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Male factor infertility (MFI) is a growing public health concern, contributing to roughly 50% of all infertility cases globally. It is clinically defined by the presence of abnormal semen parameters and is frequently characterised by low sperm count, poor sperm motility, or abnormal sperm shape.

As the prevalence of MFI rises, so too does the urgency to understand and address the modifiable risk factors that underlie it. Genetics, infections, environmental exposures and lifestyle choices are all known contributing factors, though metabolic health and obesity are becoming increasingly relevant.

How Metabolism Impacts Reproductive Health

Spermatogenesis, hormone production and overall reproductive function are highly sensitive to metabolic status. Obesity, insulin resistance and chronic low-grade inflammation are linked to lower sperm quality and reduced testosterone levels as well as impaired erectile dysfunction and reduced success of assisted reproductive technology (ART). As global obesity rates rise, so too does the urgency to understand how metabolic interventions may influence reproductive outcomes in men.

What Are GLP-1 Drugs and Why Are They So Popular?

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs), initially designed to manage type 2 diabetes, have gained widespread attention for their powerful weight loss effects. In recent years, drugs including semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) have seen a dramatic rise in off-label use for obesity treatment. This growing popularity has sparked questions about their broader physiological functions and it remains concerning that their long-term side effects are poorly understood. In particular, their influence on fertility and the reproductive system is an important though under-represented area of discussion.

Direct and long-term effects on the reproductive system remain poorly understood despite people of reproductive age increasingly turning to these medications, sometimes as part of preconception efforts.

Do GLP-1s Improve Sperm Quality? Early Clues

Emerging evidence suggests that the metabolic improvements induced by GLP-1 RAs (such as reduced insulin resistance, improved glycemic control and decreased inflammatory markers) may confer indirect benefits to fertility. For both men and women these changes can potentially lead to better hormonal balance and increased chances of natural conception.

For men specifically, weight loss via GLP-1 therapy has been associated with increased testosterone levels, improved sperm concentration and motility and reduced markers of systemic inflammation, all of which improve fertility outcomes. However, these benefits are still considered an indirect effect of weight loss and improved metabolic health rather than a direct pharmacological effect of GLP-1 on reproductive tissues.

Researchers have started looking into how GLP-1 medications (like liraglutide) affect the testicles: some studies found that men who were overweight and had low testosterone levels (a condition called hypogonadism) saw their testosterone go up and their weight go down when taking GLP-1s.

One study even showed these changes in men who had previously not responded to common treatments like testosterone or metformin.

At first, scientists thought this boost in testosterone was just thanks to the weight loss, since being healthier generally helps hormones rebalance. But the rise in testosterone was bigger than expected, suggesting the drug might also have a direct effect on the testicles themselves. This idea gained traction when researchers found GLP-1 receptors in Leydig cells, the cells in the testes that make testosterone.

There’s also evidence that GLP-1s might help with erectile function, possibly by improving blood flow.

What the Research Is Still Missing

Despite promising initial observations, there are still many unanswered questions. Research about how GLP-1 RAs may affect the male reproductive system is limited, with few studies focused on outcomes such as sperm quality, testosterone levels or male fertility rates.

Adding to this complexity is preliminary evidence that GLP-1 receptors may be expressed in reproductive tissues, indicating a possible direct effect. In the absence of comprehensive data, fertility is rarely considered a relevant outcome when prescribing these medications to men, despite their growing use in populations who may be planning families.

There is a critical need for clinical trial and longitudinal data focused on reproductive outcomes including hormone levels, sperm function and conception rates among those taking GLP-1 RAs.

The Gender Gap in GLP-1 Fertility Data

Some pharmaceutical companies have started to address gaps in knowledge surrounding reproductive health outcomes, though most efforts have focused exclusively on women.

Novo Nordisk, the manufacturer of Ozempic and Wegovy, is building a registry of women who took Wegovy whilst pregnant or nursing, tracking health outcomes through pregnancy and the first year after delivery. Eli Lilly of Mounjaro and Zepbound is undertaking a similar initiative.

However, neither programme currently investigates the impact of GLP-1 use on male fertility, leaving this significant population without data or guidance.

Until more robust evidence is available, clinicians must weigh the potential benefits of GLP-1 therapy for metabolic health against the unknowns of its impact on male reproductive health, particularly for those actively trying to conceive.

What Should Men Know Right Now?

Furthermore, long-term studies are needed to determine whether the positive changes in reproductive markers translate into improved fertility outcomes, such as increased conception rates or improved sperm integrity. The research should also explore whether any risks exist with prolonged use, including possible damaging consequences to the user or epigenetic changes that get passed to offspring. These questions are increasingly pressing since GLP-1 RAs are commonly prescribed for chronic use and, in some cases, started in adolescence or early adulthood.

Another important factor for healthcare providers to consider is the psychosocial dynamics at play. Men undergoing treatment for obesity or metabolic disease may experience stigma or diminished self-esteem, and fertility concerns may add another layer of anxiety. Empathetic discussions around known effects of this drug therapy as well as current gaps in understanding are essential to appropriately inform decision making.

The Bottom Line: Hope, Hype, and What’s Next

As these medications become more commonly prescribed to men of reproductive age, it is critical that fertility becomes recognised as a relevant clinical outcome. Healthcare providers should engage in open, evidence-based discussions with patients about their reproductive goals and the current uncertainties surrounding GLP-1 therapy.

Though the growing use of GLP-1 RAs presents an important opportunity to advance obesity management and reproductive medicine, there are many unknowns making it difficult to take a firm stance.

Until clearer evidence emerges, a cautious approach is required while research and clinical practice adapt and data continues to be published.