Do GLP-1 Weight Loss Drugs Increase Testosterone Levels?

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GLP-1 weight-loss drugs may do more than help men lose weight. Emerging research suggests that medications in this class may also increase testosterone levels in some men with obesity and metabolic hypogonadism. But does semaglutide actually boost testosterone — and could drugs such as Ozempic and Wegovy eventually have a role in men’s hormonal health?

For millions of men, low testosterone is discussed as a hormonal problem. Increasingly, however, researchers are looking at the metabolic health behind it.

Obesity, insulin resistance and type 2 diabetes are all associated with lower testosterone levels. This means that, for some men, low testosterone isn’t necessarily a problem occurring in isolation. It can be part of a much wider metabolic picture.

That has made the rapid growth of GLP-1 weight-loss drugs particularly interesting.

Originally developed to treat type 2 diabetes, GLP-1 receptor agonists are now widely used in obesity treatment. Drugs in this broader field include semaglutide, the active ingredient in Ozempic and Wegovy, and liraglutide, sold as Saxenda and Victoza.

Now researchers are asking another question: what happens to testosterone when men taking these drugs lose substantial amounts of weight and improve their metabolic health?

The early results are intriguing.

What does the research say about GLP-1 drugs and testosterone?

A 2025 systematic review and meta-analysis published in BMC Urology brought together the available evidence on GLP-1 receptor agonists and testosterone.

Researchers initially identified 1,129 articles. After screening them, only four studies met the criteria for inclusion in the final analysis.

Combined, these provided data for 219 patients before GLP-1 treatment and 216 following treatment. The average age was 47.2 years.

The researchers found a statistically significant increase in total testosterone following GLP-1 receptor agonist treatment. Bioavailable testosterone also increased significantly.

At the same time, HbA1c — a key measure of long-term blood glucose control — fell significantly.

The authors concluded that the findings point towards possible “dual metabolic and endocrine benefits” from GLP-1 therapy.

That’s potentially important. It suggests that the benefits associated with these drugs may extend beyond weight and blood sugar into hormonal health.

But there is a catch.

Free testosterone did not change significantly in the analysis, and neither did sex hormone-binding globulin (SHBG). There was also considerable variation between the studies.

So this isn’t evidence that Ozempic or Wegovy should suddenly be prescribed as testosterone treatments. Far from it.

It does, however, give researchers a compelling reason to investigate the relationship further.

Why does obesity lower testosterone?

To understand why GLP-1 drugs might affect testosterone, you first need to look at the relationship between body fat and male hormones.

Obesity is strongly associated with reduced testosterone levels. Excess body fat can affect insulin sensitivity, inflammation and the hormonal signals connecting the brain and testes.

Fat tissue also contains an enzyme called aromatase, which converts testosterone into oestrogen.

In some men, the result is obesity-related functional hypogonadism — low testosterone associated with obesity rather than permanent failure of the testes.

The word “functional” is important.

It means the hormonal problem may, at least in some cases, be reversible.

Lose enough weight, improve insulin sensitivity and reduce the metabolic disruption associated with obesity, and testosterone production may begin to recover.

That makes GLP-1 medications interesting for a reason that has relatively little to do with testosterone replacement itself.

They may be addressing one of the underlying causes of the hormonal imbalance and underlying problem.

A trial comparing liraglutide with testosterone produced surprising results

One of the most interesting studies was carried out by endocrinologist Mojca Jensterle and colleagues.

The researchers studied 30 men with obesity-associated functional hypogonadism who had not responded sufficiently to lifestyle measures.

The men had an average BMI of 41.2 and were randomly assigned to receive either the GLP-1 drug liraglutide or testosterone replacement therapy (TRT) for 16 weeks.

Testosterone increased in both groups.

Men receiving TRT experienced an average increase in total testosterone of 5.9 nmol/L. Those taking liraglutide saw an increase of 2.6 nmol/L.

On the surface, TRT therefore produced the larger testosterone increase.

But look at what happened to body weight.

The men taking liraglutide lost an average 7.9 kg during the 16 weeks.

Those receiving testosterone lost just 0.9 kg.

There was another notable difference.

Luteinising hormone (LH) and follicle-stimulating hormone (FSH) increased significantly in the liraglutide group. These hormones form part of the signalling system that stimulates the testes.

The researchers ultimately concluded that liraglutide was “superior to TRT in improving an overall health benefit” in these men after lifestyle measures had failed.

That doesn’t mean liraglutide is a better treatment for every man with low testosterone. But it illustrates an important distinction.

Testosterone therapy gives the body testosterone, whereas GLP-1 medication seems to improve testosterone levels as a side-effect of reducing body fat.

Weight-loss treatment may, in certain men with obesity-related hypogonadism, help remove some of the conditions suppressing the body’s own hormonal system.

What about GLP-1 drugs and male fertility?

This may be an even more interesting area of research.

In 2023, Sandro La Vignera and colleagues published a study involving 110 men aged between 18 and 35 with metabolic hypogonadism.

Different groups received gonadotropin therapy, liraglutide or transdermal testosterone over four months.

The researchers reported significant improvements among the men receiving liraglutide, including higher total testosterone and SHBG levels.

They also found improvements in conventional sperm parameters and erectile function.

The researchers described their results as demonstrating, for the first time, the potential efficacy of liraglutide in men with metabolic hypogonadism.

That’s particularly interesting when fertility matters.

Traditional testosterone replacement can suppress LH and FSH, reducing the signals required for sperm production. That’s why men who are trying to conceive need to discuss fertility with their doctor before starting TRT.

A treatment that improves metabolic health while allowing the body’s reproductive axis to function normally could therefore offer a very different therapeutic approach.

But again, the research remains early.

Does semaglutide increase testosterone?

This is where some online discussion gets ahead of the evidence.

It would be premature to say that semaglutide — or Ozempic specifically — has been proven to boost testosterone.

Much of the earlier clinical research in the meta-analysis involved liraglutide, not semaglutide. Three of the four studies included in the 2025 analysis used liraglutide, while another used exenatide.

The broader hypothesis is nevertheless plausible: if GLP-1-based treatment produces significant weight loss and improves insulin resistance, men whose testosterone has been suppressed by obesity may experience an improvement in their hormonal profile.

Whether GLP-1 drugs also have direct effects on the male reproductive hormonal system remains an open research question.

So are GLP-1 drugs a treatment for low testosterone?

Not currently, and TRT has more research behind it as a better solution for restoring natural testosterone levels.

The 2025 meta-analysis itself highlights the limitations of the evidence.

Only four studies were eligible for inclusion, and there was very high statistical heterogeneity for some outcomes. For total testosterone, heterogeneity reached 97%, meaning the results differed substantially between studies.

The authors called for “robust randomized controlled trials with larger cohorts and longer follow-up.”

That’s an important sentence to remember amid some of the more enthusiastic claims appearing online.

We have a signal.

We don’t yet have a definitive answer.

The bigger story may not be about “boosting” testosterone at all

Perhaps the most interesting part of this research is the way it changes the question.

Instead of asking, “How can we raise testosterone?”, clinicians may increasingly need to ask, “Why is this man’s testosterone low in the first place?”

For a man with permanent testicular or pituitary dysfunction, losing weight isn’t going to magically solve the underlying condition.

But obesity-related functional hypogonadism is different.

If metabolic dysfunction is contributing to low testosterone, treating that dysfunction may allow testosterone levels to recover naturally.

That’s why the relationship between GLP-1 drugs and testosterone deserves further attention.

These medications shouldn’t be thought of as testosterone boosters, and the current evidence certainly doesn’t justify taking a GLP-1 drug solely to increase testosterone.

But the early research points towards something potentially more significant.

For some men with obesity, improving metabolic health and losing substantial weight may help restore a hormonal system that wasn’t permanently broken — it was being suppressed by the metabolic environment around it.

As larger studies of semaglutide and other GLP-1-based therapies emerge, we’ll get a clearer picture of just how important that effect might be.

For now, the evidence suggests an intriguing connection between weight loss, metabolic health and testosterone — and one that could eventually influence how obesity-related low testosterone is treated.

Frequently Asked Questions

Do GLP-1 drugs increase testosterone?

Research suggests GLP-1 receptor agonist treatment may be associated with increases in total and bioavailable testosterone in some men, particularly those with obesity or metabolic dysfunction. However, the evidence remains limited and GLP-1 drugs are not currently approved specifically as treatments for low testosterone.

Does Ozempic increase testosterone in men?

There is not yet enough evidence to say that Ozempic itself directly increases testosterone. Research suggests that GLP-1-based treatment and the resulting weight loss and metabolic improvements may help testosterone levels recover in some men with obesity-related functional hypogonadism.

Can losing weight increase testosterone?

Yes. Weight loss has been associated with improved testosterone levels in men with obesity. This is one reason researchers believe some of the testosterone improvements observed during GLP-1 treatment may be related to weight loss and improved insulin sensitivity.

Can GLP-1 drugs improve male fertility?

Early studies have reported improvements in reproductive hormones and some sperm parameters, but there is not yet enough evidence to conclude that GLP-1 drugs are fertility treatments. Men taking testosterone or GLP-1 medications who are trying to conceive should discuss their treatment with an appropriately qualified clinician.

References

Orra SH, Martinez JVN, Porto BC, et al. Effect of GLP-1 agonists on testosterone levels: a systematic review and meta-analysis. BMC Urology. 2025;25:311. doi:10.1186/s12894-025-02005-0.

Jensterle M, Podbregar A, Goricar K, Gregoric N, Janez A. Effects of liraglutide on obesity-associated functional hypogonadism in men. Endocrine Connections. 2019;8(3):195–202. doi:10.1530/EC-18-0514.

La Vignera S, Condorelli RA, Calogero AE, Cannarella R, Aversa A. Sexual and Reproductive Outcomes in Obese Fertile Men with Functional Hypogonadism after Treatment with Liraglutide: Preliminary Results. Journal of Clinical Medicine. 2023;12(2):672. doi:10.3390/jcm12020672.

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