Ozempic and Testosterone: Does GLP-1 Raise or Lower Your T?

GLP-1 receptor agonists have become some of the most talked-about medicines in the world. Drugs like semaglutide (sold as Ozempic and Wegovy) and tirzepatide (Mounjaro and Zepbound) were developed for type 2 diabetes and obesity. Men have noticed that their testosterone numbers sometimes improve while taking them, and are asking whether that is a benefit, and whether the weight loss comes with a hidden cost.

What Are GLP-1 Receptor Agonists?

GLP-1 is a gut hormone that helps regulate blood sugar and appetite. GLP-1 receptor agonists are drugs that mimic it. Semaglutide is the active ingredient in Ozempic and Wegovy; tirzepatide, in Mounjaro and Zepbound, acts on both the GLP-1 and GIP receptors. In the STEP 1 trial of 1,961 adults with overweight or obesity and no diabetes, 68 weeks of semaglutide 2.4 mg changed body weight by -14.9 percent versus -2.4 percent with placebo, alongside lifestyle intervention. Nausea and diarrhea were the most common adverse events.^[5] In SURMOUNT-1 (2,539 adults), tirzepatide changed weight at 72 weeks by -15.0, -19.5 and -20.9 percent at 5, 10 and 15 mg versus -3.1 percent with placebo.^[6]

What Do Studies Show About Testosterone?

Obesity is linked to lower testosterone in men, so weight loss of any kind can raise it. Our body fat and testosterone guide covers this. Several reviews have looked at whether GLP-1 medicines add anything beyond weight loss:

• Meta-analysis (2025): seven studies (680 men with overweight or obesity) found a significant increase in total testosterone, with the size of the change correlated with weight and BMI reduction. The authors said the literature does not allow a direct action on the testes to be demonstrated.^[1]
• Systematic review (2026): across ten studies (639 men), total testosterone was consistently higher, particularly in men with obesity, type 2 diabetes or functional hypogonadism. Free testosterone changes were inconsistent, often offset by higher SHBG, and the authors called for longer controlled studies.^[7]
• Systematic review (2026): small randomized trials (12 to 42 men, 12 to 24 weeks) and observational studies reported increases in total testosterone of 2.5 to 5.2 nmol/L in men with obesity-related functional hypogonadism. The effect appears largely mediated by weight loss and improved insulin resistance rather than a direct androgenic action. Study quality was moderate to high risk of bias.^[8]

That ENDO 2025 analysis reviewed electronic health records of 110 men with obesity or type 2 diabetes on semaglutide, dulaglutide or tirzepatide, who were not taking testosterone, over 18 months. It was a conference presentation reported through a press release, so treat it as preliminary.^[2]

Why Might Testosterone Rise?

The leading explanation is indirect. Excess body fat is associated with lower testosterone, and weight loss reverses part of that. A meta-analysis of weight-loss studies in obese men found that diet and bariatric surgery both raised total testosterone, with larger rises in those who lost more weight.^[9] Researchers have also speculated about direct effects of GLP-1 receptors on reproductive tissue, but the reviews above conclude that this is not demonstrated.^[1][8]

The Trade-Off: Lean Mass

These drugs reduce fat, but weight loss of any kind also takes some lean mass. In a 160-person DXA substudy of SURMOUNT-1, about 75 percent of the weight lost with tirzepatide was fat and about 25 percent was lean mass.^[10] A 2026 meta-analysis of 20 randomized trials (15,782 participants) found lean mass made up 25 to 39 percent of the weight lost with incretin drugs (semaglutide 35.2 percent, tirzepatide 25.4 percent, liraglutide 26.8 percent), comparable to lifestyle interventions (26.2 percent), while lifestyle plus resistance training had the most favorable profile (17.5 percent).^[3]

The authors concluded that muscle can be significantly preserved by combining resistance training, adequate protein intake and body composition monitoring.^[3] We are not aware of evidence on how much lean mass loss affects testosterone itself, so we do not make that claim. See our guides to protein and creatine, and talk to your prescriber or a dietitian before changing your diet or starting supplements while on treatment.

Long-Term Questions

Most testosterone data cover weeks to months, not years. After withdrawal of semaglutide in the STEP 1 extension, participants regained 11.6 percentage points of the 17.3 percent weight they had lost, roughly two-thirds, and cardiometabolic improvements moved back toward baseline.^[4] If testosterone gains are driven by weight loss, it is plausible they would not persist if the weight returns, but that has not been studied well. Men who plan to have children should discuss fertility with a doctor before starting treatment.

Lifestyle Weight Loss vs Medication

Weight loss by any route is associated with higher testosterone in men with obesity.^[9] Whether to use a prescription medicine, lifestyle changes or both is a medical decision that depends on your health, BMI and history. For men with a lean build, there is no evidence these drugs help testosterone. See also our guide to testosterone and belly fat.

The Bottom Line

In men with obesity or type 2 diabetes, testosterone tends to rise as weight falls on GLP-1 medicines, but the studies are small, short and mostly show the effect tracks weight loss. These are prescription drugs prescribed for diabetes or weight management, not a way to treat low testosterone. If you have symptoms such as fatigue or low libido, ask a doctor to test your testosterone properly rather than trying to manage it yourself.

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Thrive is a wellness app that helps you build habits such as strength training, sleep and balanced eating. It is not a medical device and does not diagnose or treat any condition, and it is not a substitute for the advice of your prescriber. Learn more about Thrive.