Can Ozempic raise testosterone and improve male fertility?

If you are a man on a GLP-1 medication and you have ever wondered whether it helps or hurts your testosterone and fertility, the research finally has something to say. A 2025 meta-analysis pooled seven studies and 680 men and found that GLP-1 medications like Ozempic and Wegovy were linked to meaningfully higher testosterone and better erectile function. The catch, and it matters, is that the benefit looks like a weight-loss story more than a drug story.

TL;DR

In men with obesity and low testosterone, GLP-1 medications were associated with higher total testosterone, higher free testosterone, and improved erectile function. The gains tracked closely with weight loss, and unlike testosterone injections, the reproductive hormones LH and FSH went up rather than down. The data is early and mostly observational, so treat it as encouraging, not settled.

Why extra weight lowers testosterone in the first place

Low testosterone and obesity feed each other. Excess body fat is not inert storage. It is metabolically active tissue that runs an enzyme called aromatase, which converts testosterone into oestrogen. The more fat you carry, the more of your own testosterone gets converted away. On top of that, obesity drives chronic low-grade inflammation, and inflammatory signals dampen the messages the brain sends to the testes.

Those brain messages matter. The hypothalamus and pituitary release luteinising hormone (LH) and follicle-stimulating hormone (FSH), which tell the testes to produce testosterone and sperm. When aromatase and inflammation blunt that signalling, testosterone falls, and lower testosterone makes it easier to gain fat, which lowers testosterone further. This is called functional hypogonadism, and it is one of the most common and most reversible forms of low testosterone in men.

The reversible part is the point. If you break the cycle by losing fat, the signalling tends to recover on its own. That is the lens to read the GLP-1 findings through.

What the meta-analysis actually found

The analysis, published in the journal Andrology in 2025, combined seven studies covering 680 men with obesity, most of whom also had type 2 diabetes or low testosterone at the start. The men were treated with GLP-1 medications, mainly semaglutide and liraglutide, and their hormone levels were measured before and after. Here is what the pooled numbers showed:

• Total testosterone rose (mean difference 1.39, 95% CI 0.70 to 2.09, p<0.0001)
• Free testosterone, the fraction your body can actually use, also rose (+0.63, p=0.01)
• Luteinising hormone increased (+1.05, p=0.02) and follicle-stimulating hormone increased (+1.13, p=0.04)
• Sex hormone-binding globulin rose (+2.39, p=0.0007)
• Erectile function, measured on the IIEF questionnaire, improved by 3.31 points (p<0.00001)
• The men lost an average of 8.54 kg, dropped 2.16 points of BMI, and cut HbA1c by 1.15%

The erectile function result is worth pausing on. A 3-point gain on the IIEF is not a rounding error. It is in the range that men actually notice, and it lines up with the broader pattern that improving metabolic health improves sexual function.

Then comes the honest part. The researchers ran a meta-regression, a statistical check of what drove the testosterone gains, and found a clear link: the more weight and BMI a man lost, the more his testosterone rose. In plain terms, the medication was mostly a very effective way to lose the fat that was suppressing testosterone in the first place. Whether GLP-1 receptors act directly on the testes is still an open question the study could not answer.

The important difference from testosterone replacement therapy

This is where the fertility angle gets interesting, and where a lot of men get the wrong idea. If you take testosterone by injection or gel to treat low-T, your brain senses the extra hormone and shuts down its own signal. LH and FSH drop, the testes get smaller, and sperm production can fall sharply, sometimes to zero. That is why testosterone replacement is a poor choice for a man who still wants children, and why fertility clinics often work hard to reverse it.

The GLP-1 pattern is the opposite. In this data, LH and FSH went up, not down. The testosterone rise came from the body's own restored signalling, not from an outside supply that switches the system off. Early findings suggest that is a fundamentally more fertility-friendly way for testosterone to recover, because the machinery that also makes sperm stays switched on. The female counterpart of this story is playing out in parallel research, where GLP-1-driven weight loss appears to restore ovulation in women with PCOS - you can read our companion piece on the RESTORE fertility trial for that side.

One caution keeps this honest: only two of the seven studies measured semen quality directly, and the numbers were too thin to pool. So the reassuring signal is about the hormonal axis, not yet about proven improvements in sperm count or motility. Researchers are still investigating that piece.

What this research cannot tell you yet

Early results are encouraging, but the study authors were direct about the limits, and you should be too before drawing firm conclusions:

• Most of the included studies were observational before-and-after designs, not randomised controlled trials, so cause and effect cannot be locked down
• The total number of men, 680, is modest for a question this broad
• The studies were quite different from each other, which the authors flagged as high heterogeneity
• There was no clean way to separate the direct effect of the drug from the effect of weight loss - and the meta-regression suggests weight loss did most of the work
• GLP-1 medications are not approved to treat low testosterone or male infertility, and none of this makes them a fertility treatment

The practical read: if you are a man with obesity and low testosterone, the weight loss you get from a GLP-1 medication is likely to move your testosterone in the right direction, and it does so without the fertility trade-off that comes with testosterone injections. That is a genuinely useful thing to know. It is not a reason to start or stay on one of these drugs specifically for testosterone, and any decision like that belongs with your doctor.

The nutrition side men usually miss

Here is the gap almost nobody talks about. The whole benefit above runs on weight loss, and GLP-1 medications produce that weight loss by cutting how much you eat, in some cases by up to 40%. Eat far less food and you take in far fewer of the micronutrients that testosterone and sperm production actually depend on. You can improve the hormonal signalling and quietly starve the raw materials at the same time.

Several of these nutrients have a direct, documented role in male reproductive health, and several are among the first to run low when appetite drops on GLP-1 medications:

• Zinc is central to testosterone synthesis and sperm formation. Low zinc is one of the more consistent nutritional links to reduced testosterone and poor sperm quality, and intake falls easily when you eat less meat and shellfish.
• Selenium supports sperm motility - the ability of sperm to swim - and works alongside zinc in the testes.
• Vitamin D behaves like a hormone and is associated with testosterone levels. Deficiency is common to begin with and tends to worsen on a low food intake.
• Magnesium influences how much of your testosterone stays free and usable rather than bound up. It is one of the nutrients most reliably depleted on GLP-1 therapy, and low magnesium also feeds fatigue.
• Folate and vitamin B12 support healthy sperm DNA and cell division. B12 in particular drops on GLP-1 medications because reduced intake meets reduced absorption.

None of these are magic. A supplement will not raise your testosterone the way losing 8 kg will. But if you have done the hard part and shed the weight, it makes little sense to leave the nutritional foundation of testosterone and fertility half-built. Getting your vitamin B12, vitamin D, ferritin, and testosterone checked with a simple blood panel, and covering the gaps through food or a targeted supplement, is a low-effort way to protect the gains. GLP-1 Shield is formulated around exactly these deficiency patterns, so the nutrients your body draws on for hormone and sperm production are covered while your intake is down.

Frequently asked questions

Does Ozempic increase testosterone?

In men with obesity and low testosterone, GLP-1 medications like Ozempic and Wegovy were linked to higher testosterone in a 2025 meta-analysis of 680 men. The effect appears to be driven mostly by weight loss rather than a direct action of the drug on the testes. Testosterone rose alongside an average 8.5 kg of weight loss, and the increase was larger in men who lost more weight.

Can GLP-1 medications lower testosterone or harm fertility?

Current evidence does not show that GLP-1 medications suppress the reproductive axis. In the pooled data, luteinising hormone and follicle-stimulating hormone actually rose, which is the opposite of what happens with testosterone replacement therapy. That said, only two of the seven studies measured semen quality, so the direct effect on sperm is not yet well established.

Why does losing weight raise testosterone in men?

Excess body fat converts testosterone into oestrogen through an enzyme called aromatase and drives low-grade inflammation, both of which suppress the brain signals that tell the testes to make testosterone. Losing fat reduces aromatase activity and inflammation, so the natural signalling recovers. This is why the testosterone gains in the research tracked closely with how much weight each man lost.

What supplements support testosterone and fertility on GLP-1 medications?

Zinc, selenium, vitamin D, magnesium, folate, and vitamin B12 all play documented roles in testosterone production and sperm quality. These are also among the nutrients most easily under-eaten when GLP-1 medications cut appetite and food intake. Getting blood levels checked and covering the gaps with diet or a targeted supplement is a sensible step for men focused on reproductive health.