Does Wegovy Affect Sperm Quality or Fertility in Men?

What animal studies found, and why they only go so far

The regulatory dossier for semaglutide, reviewed by the MHRA when licensing Wegovy in the UK, included preclinical reproductive studies. In those animal experiments, high-dose semaglutide was associated with reduced fertility indices in male rodents. That sounds alarming at first glance, but the doses involved were substantially higher than the therapeutic doses used in humans, and animal reproductive biology does not map cleanly onto human physiology. Regulators assessed the data and concluded there was no specific contraindication for male fertility at licensed doses, which is why no warning to that effect appears in the standard product labelling.

It is worth checking the Mounjaro and Wegovy SmPCs on the electronic Medicines Compendium directly if you want the precise wording regulators have agreed on, the Summary of Product Characteristics is the authoritative reference, not paraphrases of it. The male fertility sections in these documents are brief precisely because the human evidence base is thin, not because the question has been answered conclusively.

In short: animal signals at high doses exist; human evidence does not yet exist; clinical risk at therapeutic doses is not established.

How weight loss itself changes the picture

This is where the question gets genuinely complicated. Obesity is an independent risk factor for lower testosterone, poorer sperm motility and reduced sperm concentration. Studies in men with obesity consistently show these patterns, and meaningful weight loss (achieved by any method, including dietary change, bariatric surgery or medication) tends to improve hormonal profiles and can improve semen parameters too.

That creates a real interpretive problem. If a man on Wegovy loses 15% of his body weight and his sperm quality improves, is that the drug helping, the drug being neutral while weight loss helps, or the drug modestly hindering while weight loss more than compensates? No published trial has controlled for this properly in a semaglutide-specific context. The honest answer is that nobody currently knows how to separate the two effects cleanly.

This is not a reason to avoid treatment if it is clinically appropriate. It is a reason to have an honest conversation with a prescriber about your reproductive goals, timing and what to monitor. Our semaglutide information page covers the broader clinical context of how the drug works.

What current guidance actually recommends for men on Wegovy

The MHRA and the NHS do not currently issue a specific warning advising men to stop Wegovy before attempting conception, unlike the guidance for women (where a wash-out period before trying to conceive is recommended). The NHS England guidance on weight-management injections addresses reproductive concerns primarily in relation to women, contraception and oral contraceptive absorption, there is no equivalent male-specific instruction at present.

That absence of specific guidance should not be read as a green light to avoid the conversation. Any man actively trying to conceive, or who has a known fertility concern, should tell their prescriber before starting treatment. The prescriber can weigh up the evidence, take a personal history and help decide whether treatment timing is appropriate. That is exactly the kind of clinical nuance that separates a regulated service with a real prescriber from a form-based process.

If cost or access is part of how you are thinking about treatment options, our Wegovy cost guide sets out what private prescriptions typically include in the UK. And if you have questions about other ways semaglutide interacts with your body (for instance, whether Wegovy affects periods or how it interacts with HRT) those pages cover the evidence in the same level of detail.

Practical steps if male fertility is on your mind

First, raise it explicitly during your consultation, not as an afterthought, but as a stated goal. A prescriber who knows you are planning a family in the next one to two years will factor that into the assessment differently than one who does not. That single piece of information changes the clinical conversation.

Second, if you are already on treatment and want a baseline, a semen analysis from a fertility clinic or GP referral gives you a concrete starting point. It takes under a minute to book a GP appointment online, and having that data makes any future comparison meaningful. That is not a reason to delay treatment if it is clinically right for you, it is just good information to have.

Third, watch for indirect signs that the drug is working well metabolically: energy, sleep quality and hormonal symptoms. There is good reason to think the metabolic benefits of weight loss flow back into reproductive health over time, even if the direct effect of semaglutide itself remains unquantified. Some patients also notice unexpected sensory changes while adjusting to treatment, and our page on whether Wegovy affects taste explores one of those experiences in detail, alongside our page on semaglutide and sleep, which covers another of those indirect markers.

Wegovy is a prescription-only medicine. A clinician decides whether it is appropriate for you, taking your full health picture into account, including any reproductive goals. If you would like that assessment, you can start a free consultation with a GPhC-registered prescriber at nume today.