GLP-1's and Fertility

Posted on July 27, 2026 by Sally-Anne Turner

What Men Need to Know

It's a topic that can make many men feel uncomfortable.

But it is an important one: fertility. In particular, fertility issues linked to being overweight or living with obesity are a concern for many people. In 2024, NHS England estimated that 29% of men in the UK were classed as overweight. The same data showed that obesity was most common among men aged 55 to 64, with 37% of men in this age group classed as overweight.

For many men in their 50s or 60s, this weight gain may be partly linked to andropause, often referred to as the male menopause, when testosterone levels begin to fall. For younger men, however, the relationship between obesity and reduced fertility can be more complex and may require clinical support to understand, manage, and treat effectively.

Our team at the Bodyline Clinic have been helping men and women on their weight loss journeys for over 18 years. We aim to help people hit their weight loss goals using our clinical expertise, support plans, and targeted lifestyle guidance. We also help men with low testosterone, which is why advancements or news about men's fertility and weight is right up our alley.

Obesity and Male Fertility

First, a bit of a biology lesson on why obesity and male fertility are linked.

If there is an increase in visceral fat in the body, this can raise an enzyme known as aromatase. Visceral body fat is stored in the abdomen. It can wrap around the liver, the intestines, the pancreas, the kidneys and the heart. Aromatase can turn testosterone into oestrogen, while also increasing inflammation. There may also be a lowering of a protein which controls the balance of oestrogen and testosterone in the body. The higher levels of oestrogen then send a chemical signal to the brain to stop signalling the testes, where testosterone is produced.

This also increases inflammation. Research conducted in 2021 noted that a constant inflammation response can suppress the hypothalamic-pituitary gonadal relationship. Why does that matter? It is the brain-to-testes stimulation pathway. Inflammation of this can slow or stop the production of testosterone.

So, is increasing testosterone via shots or supplements the answer? Kind of. But the testosterone is not the issue. Having excess visceral fat is. And according to the NHS BMI, if your BMI is over 27, you are more likely to be at risk of having excess fat and the secondary issues associated with it.

The National Institute of Clinical Excellence, or NICE, notes that being overweight increases the chances of men being diagnosed with:

1. Metabolic health issues — type 2 diabetes, prediabetes, metabolic syndrome, insulin resistance, non-alcoholic fatty liver disease, metabolic dysfunction-associated steatohepatitis.
2. Cardiovascular health — high blood pressure (hypertension), high cholesterol, coronary heart disease, heart attacks, strokes, heart failure, atrial fibrillation.
3. Hormonal and reproductive health — reduced testosterone, erectile dysfunction (ED), reduction in libido, lower sperm count, poor sperm morphology (shape), reduced sperm motility.
4. Respiratory health — issues like obstructive sleep apnoea increase, as do issues related to reduced lung function and breathlessness.
5. Musculoskeletal health — men who are overweight have a higher chance of developing reduced mobility, osteoarthritis (usually of the knees and hips), chronic back pain and joint pain.
6. Mental health — depression, anxiety, low self-esteem and poor body image occur in as many as 25% of men who are overweight, according to Ipsos.
7. Digestive and liver health — common co-morbidities with obesity can be gallstones, gastro-oesophageal reflux disease (GERD), cirrhosis and liver fibrosis.
8. Kidney health — the risks of both kidney stones and chronic kidney disease increase in men who are larger.
9. Cancer risk — cancer risks increase with kidney, bowel, liver, pancreatic and oesophageal cancer being among the most common.

GLP-1s and Testosterone

It is a common concern for both men and women who are taking GLP-1s.

Do these pills or injections impact fertility? After all, Novo Nordisk has stated that women who are intending to get pregnant should stop taking the Wegovy pill 3 months before they are trying to conceive. And, if a woman is pregnant, she should stop taking this GLP-1.

So, do GLP-1s have an impact on men's fertility? They seem to, but not in the way many men may think. Yes, GLP-1s impact all parts of the body and, luckily, researchers have kept an eye on how GLP-1s interact with hormones like testosterone.

A study that was published in 2026 by Endocrine Abstracts highlighted that for men, semaglutide was more effective than testosterone replacement therapy. The study, which was conducted by University Hospitals Coventry and Warwickshire NHS Trust and Warwick Medical School, University of Warwick, was presented at ENDO 2026 and highlighted that over 24 weeks of GLP-1 treatment, men experienced:

1. Improved testosterone levels
2. Improved sperm count
3. Improved sperm morphology (the shape and structure of sperm)
4. Potential improvements in overall fertility markers, particularly in men with obesity and metabolic dysfunction

In a similar vein, a study from 2024 that was published by Reproductive Biology and Endocrinology looked at semaglutide and compared it to testosterone replacement therapy (TRT) in men who were diagnosed with obesity, type 2 diabetes and functional hypogonadism.

Over 24 weeks, this study found that:

1. Semaglutide improved sperm morphology. The percentage of normally shaped sperm increased from 2% to 4% after 24 weeks of weekly injections.
2. Both semaglutide and TRT increased testosterone levels. This highlights that semaglutide is comparable to testosterone therapy for managing hypogonadism.
3. TRT reduced both sperm concentration and the overall sperm count. However, semaglutide preserved fertility markers. Thus, it is a more fertility-friendly treatment.
4. Also, men who were taking semaglutide achieved significant weight loss. This supports the effectiveness of treating obesity or being overweight, while also helping hormones improve.

The research team also concluded that semaglutide was a promising treatment for men with obesity-related functional hypogonadism who wished to preserve their fertility. Unlike TRT, semaglutide increased testosterone levels in the participants while also preserving sperm quality. So, semaglutide may offer a fertility-sparing approach for men who are overweight and may have obesity-related low testosterone.

Do Injections Have More Impact than the Pills?

As of July 2026, there has been a change in how people in the UK take GLP-1s.

The Wegovy pill is the first in a line of upcoming pill-related semaglutide medications. Based on statements coming out of Novo Nordisk, the pharmaceutical company has written over 600,000 new prescriptions for this pill.

In short, it seems that the average person who wants to lose weight wants to do so via a pill, rather than an injection. This is likely due to many people not liking needles or seeing injections as being more serious than taking a pill. If you are a man who is looking into medicated weight loss treatment and wants to preserve your fertility, you may be questioning which administering route has the greater impact on testosterone and secondary fertility.

At the time of writing, the only information we have relating to semaglutide route of administration and fertility is that there is no comparison data between the injections and the pills. Both of the aforementioned studies used injectable semaglutide.

However, research does point to the pills and the injections having a similar impact. Both injectable and oral GLP-1s:

1. Activate the GLP-1 receptor
2. Improve insulin sensitivity
3. Reduce body weight
4. Reduce visceral fat
5. Improve metabolic health

All of these are considered to be the reasons why fertility markers improve. Of course, for oral GLP-1s, you would need to have a higher dose than the injectables, due to how the dose hits the bloodstream. Check out our article on the Wegovy pill vs injection for more information on that and to learn more about Wegovy UK side effects.

Are GLP-1s The Next Fertility Treatment?

It is important not to get too far ahead here, but it is a question that is worth asking.

At the time of writing, the NHS treats issues with male infertility with the following options:

1. Lifestyle changes, such as having a low-fat diet, regular exercise, reducing alcohol, smoking cessation and avoiding recreational drugs.
2. Prescribing medication, such as for hormonal issues or infections. TRT is generally not used for men who are trying to have kids, as it can suppress sperm production.
3. Surgery can correct issues, such as a varicocele (enlarged veins in the scrotum). Or it may be based around repairing blockages if applicable.
4. Assisted reproductive technologies (ART) like intrauterine insemination (IUI), in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI). This will vary based on the cause of infertility.
5. Weight management support is ideal for men who have fertility issues potentially linked to obesity.

At the time of writing, to be eligible for NHS weight loss injections, you need to have a BMI of 40 or higher, and have at least four of the following five long-term conditions:

1. Type 2 diabetes
2. High blood pressure
3. Heart disease
4. High cholesterol
5. Sleep apnoea

There is no information at present as to the criteria that will be needed on the NHS to access oral GLP-1s. But watch this space!

Why Choose Bodyline?

When it comes to weight loss, there are lots of online services out there that can help you hit your weight goals. So why come to the Bodyline Clinic?

We have helped over 100,000 patients across the UK to do just that already, and our clinical team has over 18 years of expertise in this area. We take the time to get to know you and assess your health to choose the most appropriate weight loss option for you, as well as offering ongoing support.

Weight loss is not just about losing weight. It is a journey that requires care. And if you've been unsuccessful in the past, we can help you. Contact us today for more information.

FAQs

Why Does Being Overweight Impact a Man's Fertility?

Research shows that being overweight can indeed impact a man's fertility. Primarily, having excess visceral fat can:

1. Raise an enzyme known as aromatase, which turns testosterone into oestrogen.
2. Lower a protein which controls how much oestrogen and testosterone there is in the body.
3. Increase inflammation. Specifically, the inflammation can suppress the hypothalamic-pituitary gonadal relationship. This stops the production of testosterone.

What Health Issues Are Linked to Being Overweight?

In men, NICE has found that being overweight is linked to:

1. Metabolic health issues
2. Cardiovascular health
3. Hormonal and reproductive health
4. Respiratory health
5. Musculoskeletal health
6. Mental health
7. Digestive and liver health
8. Kidney issues
9. A higher risk of developing cancer

Do Testosterone Injections Help with Fertility?

It can, but interestingly, studies have compared GLP-1s to testosterone shots. Over 24 weeks of having GLP-1 injections, men experienced:

1. Higher testosterone levels
2. Improved sperm count
3. Improved sperm shape and structure
4. Improvements in fertility markers

Can GLP-1s Improve Fertility in Men?

It is too early in research to state clearly that taking a GLP-1 can improve fertility in all men. The studies show that in men who are overweight, taking a GLP-1 can treat conditions that have an impact on their fertility, such as inflammation and excess visceral fat.