GLP-1 Medications and Male Fertility: What the Research Shows

For men on semaglutide who are thinking about starting a family, one question comes up regularly: does this medication affect my fertility? Current research on GLP-1 medications and male fertility suggests the answer is mostly reassuring, and in many cases, points toward meaningful reproductive benefits for men with obesity.

*This article is for informational and educational purposes only. It is not medical advice. Compounded [semaglutide](/weight-loss/semaglutide/) and tirzepatide are not FDA-approved medications. The clinical research cited here was conducted using FDA-approved branded formulations. Results from studies of FDA-approved medications may not apply to compounded products. Individual results vary. Consult your licensed healthcare provider before starting, stopping, or adjusting any medication. Blue Oak Services LLC dba Prescriva is a management services organization and does not practice medicine or employ physicians.*

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Male fertility accounts for roughly half of all infertility cases. Yet it receives far less public attention than female reproductive health, and the conversation around how weight loss medications affect it is only beginning. GLP-1 receptor agonists, including semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound), are now among the most prescribed medications in the United States, and many of the men taking them are in their prime reproductive years.

This article documents what the current research shows about GLP-1 medications and male reproductive health, covering testosterone levels, sperm quality, the underlying biology, and what men trying to conceive should discuss with their provider.

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The Connection Between Obesity and Male Fertility

Before examining what GLP-1 medications do, it helps to understand what excess body fat does to the male reproductive system. The mechanisms are well-established and explain why weight loss, by any sustained means, tends to improve male reproductive hormones.

The aromatase pathway. Adipose (fat) tissue contains an enzyme called aromatase, which converts testosterone into estradiol (a form of estrogen). The more fat tissue a man carries, particularly visceral abdominal fat, the more aromatase activity occurs. This conversion shifts the testosterone-to-estrogen ratio in a direction that suppresses normal male hormonal function.

Suppression of the HPG axis. Elevated estrogen from peripheral aromatization feeds back negatively to the hypothalamic-pituitary-gonadal (HPG) axis. The hypothalamus reduces its output of gonadotropin-releasing hormone (GnRH). The pituitary follows by secreting less luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH drives testosterone production in Leydig cells; FSH drives sperm production in Sertoli cells. When both signals fall, both testosterone and sperm production decline.

Functional hypogonadism. The result in many men with significant obesity is a condition called obesity-associated functional hypogonadism: low testosterone without a primary testicular defect. Unlike classical hypogonadism, this form is potentially reversible with sufficient weight loss because the underlying cause (excess aromatase activity and HPG suppression) can be removed.

Effects on sperm. Obesity is also directly associated with poorer semen parameters. A 2025 meta-analysis in Frontiers in Endocrinology analyzing data across multiple studies found that higher BMI was independently associated with reduced sperm motility, decreased sperm concentration, and worse sperm morphology in men ([PMID: 41427049](https://pubmed.ncbi.nlm.nih.gov/41427049/)). The proposed mechanisms include elevated scrotal temperature from excess adipose tissue, increased oxidative stress in seminal plasma, elevated estrogen suppressing spermatogenesis, and direct metabolic effects on Sertoli cell function.

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What GLP-1 Medications Do for Male Reproductive Hormones

The primary pathway through which GLP-1 medications benefit male reproductive health is weight loss. By reducing body fat, these medications reduce aromatase activity, which reduces estrogen excess, which allows the HPG axis to recover. Testosterone production rises, and sperm quality can improve in parallel.

But there is a secondary pathway that researchers have been investigating: direct effects of GLP-1 receptor signaling on reproductive tissue.

GLP-1 receptors in testicular tissue. Multiple studies have now confirmed the presence of GLP-1 receptors in the testes, including in Leydig cells (the testosterone-producing cells). A 2025 study in the International Journal of Molecular Sciences demonstrated that pharmacological doses of liraglutide improved mitochondrial function in mouse Leydig cells, suggesting that GLP-1R activation may support steroidogenesis (testosterone synthesis) independently of weight changes ([PMID: 41009468](https://pubmed.ncbi.nlm.nih.gov/41009468/)). Whether this mechanism translates clinically in humans at the doses used for weight management remains an open question, but the receptor biology provides a plausible mechanistic foundation for direct effects.

Systematic review evidence. A 2026 systematic review published in the Journal of Sexual Medicine examined the effects of GLP-1 receptor agonists on male reproductive hormones, semen parameters, and metabolic outcomes across available clinical studies. The review found consistent evidence that GLP-1 medications increased total and free testosterone concentrations in men with obesity and functional hypogonadism, with improvements correlating with the degree of weight loss achieved ([PMID: 41498523](https://pubmed.ncbi.nlm.nih.gov/41498523/)). The authors concluded that the testosterone improvements were primarily mediated through fat mass reduction but could not rule out direct receptor-level contributions.

A broader meta-analysis. A 2026 systematic review and meta-analysis in the journal Andrology specifically pooled data on male sexual hormones from GLP-1 receptor agonist and SGLT2 inhibitor studies. The findings for the GLP-1 class showed statistically significant increases in testosterone levels, with effect sizes that were clinically meaningful in the context of functional hypogonadism treatment ([PMID: 42011503](https://pubmed.ncbi.nlm.nih.gov/42011503/)). A 2025 review in Aging Male framed these findings as part of a broader "hormone reset" that GLP-1 medications appear to facilitate in men with metabolic obesity ([PMID: 41399135](https://pubmed.ncbi.nlm.nih.gov/41399135/)).

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What Studies Show About Sperm Quality

The evidence on sperm quality is less mature than the evidence on testosterone, but the data that exist are encouraging.

The Gregorič study on semaglutide and sperm morphology. A 2025 clinical study published in Diabetes, Obesity and Metabolism evaluated men with obesity, type 2 diabetes, and functional hypogonadism who were treated with semaglutide. Researchers tracked semen parameters over the treatment period and found significant improvements in sperm morphology (the percentage of sperm with normal shape) alongside weight loss and testosterone normalization ([PMID: 39511836](https://pubmed.ncbi.nlm.nih.gov/39511836/)). This is one of the most directly relevant studies to date, as it specifically examined semaglutide rather than the class more broadly, and measured sperm parameters as a primary endpoint.

Preclinical safety data. A 2025 study in the journal Endocrine used mouse models and cell lines to evaluate whether GLP-1 receptor agonists had detrimental effects on sperm quality. The study found no evidence of harm to spermatogenesis at doses equivalent to those used clinically, which is important safety context even if animal findings do not fully predict human outcomes ([PMID: 40347306](https://pubmed.ncbi.nlm.nih.gov/40347306/)).

Obesity's effect on IVF outcomes. For men whose partners are undergoing assisted reproduction, paternal weight matters. A 2022 systematic review and meta-analysis in the Journal of Obstetrics and Gynaecology Research found that elevated paternal BMI was independently associated with worse IVF outcomes, including lower fertilization rates, reduced blastocyst development, and higher miscarriage risk ([PMID: 35678371](https://pubmed.ncbi.nlm.nih.gov/35678371/)). Weight loss prior to attempting conception or IVF may therefore improve outcomes from both the male and female side.

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GLP-1 Medications and Testosterone Levels

For men primarily concerned about testosterone rather than fertility, the picture is similarly encouraging. [Research specifically examining GLP-1 medications and testosterone](/articles/glp1-medications-testosterone-hypogonadism) in men with obesity-related hypogonadism has found consistent improvements.

A 2026 study in Endocrine Practice examined testosterone responses specifically to incretin-based weight loss medications (GLP-1 receptor agonists and dual agonists) in men, finding that significant weight loss produced clinically meaningful testosterone increases in most subjects with pre-treatment functional hypogonadism ([PMID: 41544705](https://pubmed.ncbi.nlm.nih.gov/41544705/)). Men with more severe obesity and more pronounced HPG suppression at baseline tended to see the largest hormonal recovery.

For men concerned about [erectile function](/articles/glp1-medications-erectile-dysfunction), the vascular and hormonal improvements associated with significant weight loss on GLP-1 medications may also provide some benefit, though that topic is covered in more depth in the linked article.

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What This Means for Men Trying to Conceive

For men who are actively trying to conceive, the body of research suggests several practical takeaways.

Weight loss improves male reproductive parameters. GLP-1 medications are among the most effective tools available for sustained significant weight loss. Men with obesity-related functional hypogonadism or poor semen parameters who achieve meaningful weight loss through any means, including GLP-1 therapy, can expect improvements in testosterone and potentially in sperm quality.

There is no direct evidence that GLP-1 medications impair male fertility. The available data, including preclinical safety studies, clinical semen parameter analyses, and systematic reviews of reproductive hormone outcomes, do not point toward harm. The 2025 Urology review on GLP-1 receptor agonists and male fertility concluded that current evidence does not support concerns about GLP-1-induced reproductive toxicity in men ([PMID: 41016449](https://pubmed.ncbi.nlm.nih.gov/41016449/)).

Weight loss prior to IVF may improve paternal contribution to embryo quality. For couples pursuing assisted reproduction, a period of weight loss in the male partner before sperm collection may improve semen parameters and embryo development outcomes. This is worth discussing with a reproductive specialist.

A 2025 review in Human Reproduction examined weight loss interventions specifically for obesity-related male infertility and found that men who achieved 10 percent or greater body weight reduction showed the most consistent improvements in sperm concentration, motility, and morphology, regardless of the method of weight loss ([PMID: 41024420](https://pubmed.ncbi.nlm.nih.gov/41024420/)).

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When to Stop GLP-1 Medications Before Conception

This is an important practical question, and current FDA guidance is clear: semaglutide and tirzepatide should be discontinued before attempting to conceive. The prescribing information for both medications recommends stopping the medication at least two months before a planned pregnancy due to the lack of adequate data on human fetal exposure and preclinical findings in animal reproduction studies showing fetal risk at high doses.

This guidance applies regardless of gender. Men taking GLP-1 medications who are actively trying to conceive with a partner should discuss timing with their provider. The two-month window before active conception attempts is the most commonly cited clinical recommendation, allowing the medication to clear the system before sperm involved in conception are produced. Sperm production (spermatogenesis) takes approximately 74 days, meaning that stopping GLP-1 therapy two to three months before beginning active conception attempts ensures that mature sperm were not developing under GLP-1 exposure.

There are no large-scale human studies on paternal GLP-1 exposure and pregnancy outcomes. This is an area of ongoing research. Until more data are available, following FDA guidance and discussing individual timing with a healthcare provider is the appropriate approach.

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FAQ

Does semaglutide affect male fertility? Current research does not indicate that semaglutide harms male fertility. In men with obesity and functional hypogonadism, semaglutide has been associated with improvements in testosterone levels and sperm morphology through weight loss. FDA guidance recommends discontinuing the medication before attempting conception as a precaution given limited human reproductive safety data.

Can GLP-1 medications improve testosterone in men? Multiple systematic reviews and clinical studies have found that GLP-1 medications increase testosterone levels in men with obesity-related functional hypogonadism. The improvements are primarily driven by fat mass reduction, which reduces aromatase-mediated testosterone-to-estrogen conversion and allows the HPG axis to recover. Men with more severe obesity tend to see the largest testosterone increases.

Does obesity reduce sperm quality? Yes. A 2025 meta-analysis confirmed that higher BMI is independently associated with reduced sperm motility, concentration, and morphology. The proposed mechanisms include elevated scrotal temperature, oxidative stress in seminal plasma, and hormonal disruption from excess aromatase activity in adipose tissue.

How long before trying to conceive should I stop semaglutide? FDA prescribing information recommends stopping semaglutide and tirzepatide at least two months before a planned pregnancy. For men, this timing aligns with the approximately 74-day spermatogenesis cycle. Discuss your specific situation and timing with your prescribing provider.

Is tirzepatide safe for male fertility? Tirzepatide (Mounjaro, Zepbound) carries similar reproductive safety guidance to semaglutide: discontinue before attempting conception. The research on tirzepatide's specific effects on male reproductive parameters is more limited than semaglutide data, but the mechanisms (weight loss, HPG axis recovery) are expected to be similar. The GLP-1 and GIP receptor pathways tirzepatide activates both appear in testicular tissue.

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Conclusion

The research on GLP-1 medications and male fertility is still developing, but several things are clear. Obesity impairs male reproductive health through well-understood hormonal mechanisms, including aromatase-driven testosterone-to-estrogen conversion and HPG axis suppression. GLP-1 medications, through their effects on body weight, can reverse these mechanisms and improve testosterone levels and, in some studies, sperm quality. There is no current evidence that these medications directly harm male reproductive function.

For men on semaglutide or tirzepatide who are thinking about starting a family, the most important step is an honest conversation with their healthcare provider about timing, the two-month pre-conception stopping window, and whether pre-conception male reproductive evaluation makes sense given their clinical picture.

If you are considering compounded GLP-1 medications as part of your metabolic health journey and have questions about how treatment fits with your reproductive goals, Prescriva's provider team can help you think through the timing and approach.

*This article is for educational purposes only and does not constitute medical advice. Individual results vary. Consult your licensed healthcare provider before starting, stopping, or adjusting any medication.*