If you take a medicine for diabetes or weight management, you may wonder whether it could affect your sperm, testosterone or sex life—particularly if you are planning a family.
The effects on male reproductive health remain uncertain. Available studies are limited, involve different medicines and patient groups, and sometimes report conflicting findings. Changes in laboratory measurements do not establish whether treatment increases the chance of pregnancy or live birth.[1–7]
An improvement in testosterone, sperm quality or erections is not the same as proven improvement in fertility.
Which medicines are we discussing?
Ozempic and Wegovy contain semaglutide, which acts on the GLP-1 receptor. Mounjaro contains tirzepatide, which acts on both GIP and GLP-1 receptors. These pathways help regulate appetite and blood glucose.
They are prescription medicines used for specific metabolic conditions. The names are included to help readers identify medicines they may already take. This article does not recommend starting them to treat infertility, low testosterone or erectile dysfunction. It addresses reproductive-health questions, not their complete benefits, side effects, contraindications or suitability for an individual. Discuss these with your prescriber and consult the current Consumer Medicine Information for your medicine.
Why weight and diabetes matter
Obesity can affect hormone regulation and is associated with poorer semen quality. Diabetes and other metabolic conditions can also contribute to sexual difficulties. This makes it difficult to separate the effect of a medicine from the condition being treated.[5,8]
Urological guidelines recommend addressing relevant lifestyle and health factors as part of male fertility care. However, fertility difficulties should not automatically be attributed to weight: other causes may need investigation.[8]
Do these medicines affect sperm count or quality?
Semaglutide: a small study, with important limitations
A 2025 randomised study included 25 men with obesity, type 2 diabetes and low testosterone related to their metabolic health. Participants received semaglutide or testosterone treatment for 24 weeks.[1]
The semaglutide group showed an improvement in the proportion of normally shaped sperm. However, the study was small, had no placebo group and did not establish improved pregnancy or live-birth rates. Testosterone was also a challenging comparison because it can suppress sperm production.[1]
These findings cannot establish how semaglutide affects every man, or whether different doses and patient groups have the same results.
Weight loss itself may explain some changes
In a separate study, men with obesity had an increase in sperm concentration and total sperm count after an initial low-calorie diet. Improvements persisted among men who maintained their weight loss over the following year.[2]
The maintenance phase included exercise and/or liraglutide, another GLP-1 medicine. Because sperm measures improved before the medicine phase, this study does not prove that a medicine directly improved sperm production. It also cannot be treated as direct evidence about semaglutide or tirzepatide.[2]
What do we know about tirzepatide and fertility?
A short pilot study of tirzepatide assessed hormones and sexual-function scores, but not sperm quality or pregnancy outcomes.[3]
Its results therefore cannot answer whether tirzepatide improves or harms fertility. The product information states that its effect on human fertility is unknown.[9]
If you have an abnormal semen result, a male fertility assessment can help identify possible causes rather than assuming a medicine is responsible.
Can they raise or lower testosterone?
Small studies have reported increases in testosterone in selected men with obesity and metabolic health problems, but they do not establish a predictable effect for all men.[1,3] The database study discussed below also reported more recorded diagnoses of testosterone deficiency among semaglutide users; it cannot establish that the medicine caused those diagnoses.[4]
The tirzepatide pilot study included 83 men across three groups, with 28 receiving tirzepatide. Hormone measurements and erection questionnaire scores improved over two months. However, treatment allocation was not random, the groups differed at baseline and follow-up was short.[3]
These findings are preliminary. They do not establish a reliable testosterone benefit for an individual patient or justify prescribing these medicines specifically for low testosterone.
Obesity can lower the blood protein that carries testosterone, called SHBG. This means a total testosterone result needs careful interpretation. Diagnosis usually requires compatible symptoms and repeat morning blood tests, with additional hormone testing where appropriate.[10]
Testosterone treatment needs particular care when planning children
Testosterone injections or gels can suppress the signals needed for sperm production, sometimes causing very low sperm counts or no sperm in the ejaculate. Urological guidelines advise against testosterone therapy in men seeking fertility.[8,10]
Tell your treating doctor about current or future family plans before starting hormone treatment.
What does research show about erection problems?
The evidence is mixed.
A database study compared 3,094 men prescribed semaglutide with a matched group of men with obesity who did not receive it. The men were aged 18–50 and did not have diabetes. A new erectile dysfunction diagnosis or prescription for erection medication was recorded in 1.47% of semaglutide users versus 0.32% of controls.[4]
These are recorded study outcomes, not a reliable estimate of an individual patient’s risk. This was an association, not proof that semaglutide caused the problem. Medical records cannot fully account for differences in health, healthcare contact or other influences.
A 2026 study in men with type 2 diabetes also found a modest association between GLP-1 treatment and recorded erectile dysfunction. However, the association was no longer statistically significant after an additional analysis designed to account for bias.[5]
Other research points in the opposite direction: an exploratory analysis of a randomised trial found a small reduction in moderate or severe erectile dysfunction with dulaglutide. That involved a different medicine and cannot be assumed to apply to semaglutide or tirzepatide.[6]
If erections change after starting treatment, discuss the timing with your prescriber. A medication review and assessment for other causes are more useful than assuming either that the medicine is responsible or that the symptom is unrelated. Read more about erectile dysfunction assessment.
Should men stop treatment before trying for a baby?
Do not stop or change prescribed treatment without discussing it with your treating doctor.
Product advice about stopping semaglutide before a planned pregnancy relates to the person who will become pregnant. It should not automatically be applied to a male partner.[11]
There is no established universal stopping interval for men based on the studies discussed here. Evidence on paternal exposure and pregnancy outcomes remains limited, so this is not a guarantee of zero risk.[7]
An individual review should consider why the medicine was prescribed, symptom changes, semen results and the couple’s fertility timeline.
When is a male fertility or hormone assessment useful?
Your GP or prescribing clinician can review concerns and advise whether specialist assessment is appropriate. Reasons to discuss assessment include:
Difficulty conceiving or an abnormal semen analysis.
Persistent erection problems, reduced sexual desire or symptoms suggesting low testosterone.
A history of testicular problems or previous testosterone or anabolic steroid use.
Concerns about medication while preparing for fertility treatment.
Assessment may include medical and reproductive history, examination, semen analysis and selected hormone tests. Not every man taking these medicines needs fertility testing. Investigations should reflect symptoms and reproductive plans.[8]
Bring your medication list, the dates treatment started or changed, previous semen results and any hormone blood tests. Where fertility is a concern, both partners’ circumstances should guide the timing of assessment.[8]
Frequently asked questions
Does a higher testosterone level mean better fertility?
No. A testosterone blood test cannot measure fertility. In particular, prescribed testosterone may increase blood testosterone while suppressing sperm production.[8,10]
Can I assume better sperm morphology means a better chance of pregnancy?
No. Morphology describes sperm appearance. A change in this measurement does not by itself establish a higher chance of conception or live birth.[1,7]
Should I postpone IVF while trying to lose weight?
Do not postpone fertility treatment solely because these medicines might improve semen results. The decision should consider both partners, including age, ovarian reserve and the cause of infertility. Metabolic care and fertility assessment can often proceed together.[8]
Male fertility and sexual-health care in Brisbane
Dr Jack Crozier is a specialist urologist in Brisbane whose clinical interests include andrology, male infertility and erectile dysfunction.
If specialist assessment is appropriate for abnormal semen results, difficulty conceiving or persistent sexual symptoms, appointment information is available. Taking one of these medicines alone does not mean you need specialist review, hormone testing or semen analysis.
Patients travelling from regional Queensland, interstate or overseas can ask the rooms about appropriate initial arrangements and the records required before travelling. Information for international patients explains the available enquiry pathway.
References
Gregorič N, Šikonja J, Janež A, Jensterle M. Semaglutide improved sperm morphology in obese men with type 2 diabetes mellitus and functional hypogonadism. Diabetes Obes Metab. 2025;27(2):519–528. doi:[10.1111/dom.16042](https://doi.org/10.1111/dom.16042).
Andersen E, Juhl CR, Kjøller ET, Lundgren JR, Janus C, Dehestani Y, et al. Sperm count is increased by diet-induced weight loss and maintained by exercise or GLP-1 analogue treatment: a randomized controlled trial. Hum Reprod. 2022;37(7):1414–1422. doi:[10.1093/humrep/deac096](https://doi.org/10.1093/humrep/deac096).
La Vignera S, Cannarella R, Garofalo V, Crafa A, Barbagallo F, Condorelli RA, et al. Short-term impact of tirzepatide on metabolic hypogonadism and body composition in patients with obesity: a controlled pilot study. Reprod Biol Endocrinol. 2025;23:92. doi:[10.1186/s12958-025-01425-9](https://doi.org/10.1186/s12958-025-01425-9).
Able C, Liao B, Saffati G, et al. Prescribing semaglutide for weight loss in non-diabetic, obese patients is associated with an increased risk of erectile dysfunction: a TriNetX database study. Int J Impot Res. 2025;37:315–319. doi:[10.1038/s41443-024-00895-6](https://doi.org/10.1038/s41443-024-00895-6).
Tang H, Lu Y, Zhang B, Zhang D, Asch DA, Chen Y. GLP-1 receptor agonist and risk of erectile dysfunction in men with type 2 diabetes: a target trial emulation. EClinicalMedicine. 2026;94:103857. doi:[10.1016/j.eclinm.2026.103857](https://doi.org/10.1016/j.eclinm.2026.103857).
Bajaj HS, Gerstein HC, Rao-Melacini P, Basile J, Colhoun H, Conget I, et al. Erectile function in men with type 2 diabetes treated with dulaglutide: an exploratory analysis of the REWIND placebo-controlled randomised trial. Lancet Diabetes Endocrinol. 2021;9(8):484–490. doi:[10.1016/S2213-8587(21)00115-7](https://doi.org/10.1016/S2213-8587(21)00115-7).
Kaltsas A, Gkioxaris V, Giannakas T, Zachariou A, Dimitriadis F, Sofikitis N, et al. GLP-1 receptor agonists and tirzepatide in men seeking fertility: a structured narrative review and proposed clinical framework. J Clin Med. 2026;15(18):7313. doi:[10.3390/jcm15187313](https://doi.org/10.3390/jcm15187313).
European Association of Urology. EAU guidelines on sexual and reproductive health: male infertility [Internet]. 2026 [cited 2026 Nov 6]. Available from: https://uroweb.org/guidelines/sexual-and-reproductive-health/chapter/male-infertility.
Eli Lilly and Company Limited. Mounjaro KwikPen: summary of product characteristics [Internet]. Electronic Medicines Compendium [cited 2026 Nov 6]. Available from: https://www.medicines.org.uk/emc/product/15484/smpc.
European Association of Urology. EAU guidelines on sexual and reproductive health: male hypogonadism [Internet]. 2026 [cited 2026 Nov 6]. Available from: https://uroweb.org/guidelines/sexual-and-reproductive-health/chapter/male-hypogonadism.
Novo Nordisk Limited. Wegovy FlexTouch: summary of product characteristics [Internet]. Electronic Medicines Compendium [cited 2026 Nov 6]. Available from: https://www.medicines.org.uk/emc/product/13801/smpc.
Medical disclaimer
This article provides general education and does not replace individual medical advice, examination or treatment. Evidence about these medicines and male reproductive health is evolving. Medicines are mentioned to explain published research. This article does not establish their suitability for any individual or provide a complete account of their risks and adverse effects. Do not start, stop or change prescribed treatment without advice from your treating clinician. Assessment and treatment depend on individual circumstances; fertility, hormonal and sexual outcomes cannot be guaranteed. Medicine approvals and healthcare arrangements differ between countries. International patients should also seek advice from their local treating clinician.
