GLP-1 and Men's Health: Testosterone, Erections, Sperm and Muscle
Post hoc analyses reported in a conference abstract suggest women lose about 40% more weight than men on GLP-1 drugs. A review of five trials found no negative impact on hormones, sexual function or sperm quality, with possible testosterone gains for men whose low T is driven by obesity [1][10].
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On the weight-loss question, the short answer is yes: men tend to lose somewhat less than women on the same GLP-1 drug. Post hoc analyses indicate women achieve roughly 40% greater weight-loss reductions than men on GLP-1 receptor agonists [1]. In the SELECT trial, men showed consistent weight loss across ages 45 to 90 [1].
On the other questions men ask about, the picture is mostly reassuring but early. A review of five randomized trials, presented at the ENDO 2026 conference and described in an Endocrine Society press release, found GLP-1 drugs had no negative impact on hormones, sexual function or sperm quality after long-term use, and men with obesity-related low testosterone saw testosterone rise — likely because weight loss treats the underlying cause [10]. A large records study found tirzepatide was associated with a lower risk of erectile dysfunction in men with type 2 diabetes compared with several other diabetes drugs [7]. The main caution is muscle: these drugs cause rapid, significant loss of lean mass along with fat, and researchers argue resistance exercise is the key countermeasure [11].
Do men lose less weight than women on semaglutide?
Yes, on average. A conference abstract presented at ADA 2026 and published in Diabetes (75 Supplement 1) analyzed pooled data from the STEP 1 trial (n=1,482) and the SELECT trial (n=17,604) — adults with overweight or obesity but without type 2 diabetes, randomized to semaglutide 2.4 mg or placebo. Post hoc analyses indicated women achieved about 40% greater weight-loss reductions than men [1].
Importantly, the sex difference was not fully explained by drug exposure — meaning men’s smaller losses do not appear to be simply a matter of getting less drug into their system [1]. In SELECT, men showed consistent weight loss across ages 45 to 90, while women’s weight loss decreased with age. Circulating FSH and LH (hormones that mark menopausal status) predicted weight-loss magnitude in women, especially during perimenopause (p<0.05). A small subgroup of STEP 1 participants over 55 on estradiol hormone replacement therapy (n=30) lost 20% of body weight versus 16% in matched controls (p=0.009) [1].
The authors concluded that multiple factors contribute to the sex difference, that menopausal status is a key determinant in women, and that larger studies are warranted. One caveat: this is a conference abstract, not a full peer-reviewed paper [1].
Does weight loss on these drugs raise testosterone in men?
It can, if low testosterone is driven by excess weight. A review presented at ENDO 2026 by researchers from Warwick Medical School and University Hospitals Coventry and Warwickshire searched medical databases for randomized controlled trials comparing GLP-1 drugs with other treatments or placebo in men aged 18 to 65. Five trials met their eligibility criteria, checked by two independent reviewers [10].
In one 16-week liraglutide study in men with obesity and weight-related low testosterone, the men experienced increases in testosterone and related hormones — and their overall outcomes were better than with testosterone replacement alone [10]. A separate 24-week semaglutide study showed improvements in sperm shape and cholesterol, while testosterone and hormone levels stayed stable [10].
Two systematic reviews add context. One, following PRISMA 2020 guidelines by La Vignera and Condorelli at the University of Catania (published in Pharmaceuticals in 2026), maps the mechanisms linking male hypogonadism to incretin therapy response, including proposed and indirect pathways [2]. Another in The Journal of Sexual Medicine covers GLP-1 receptor agonist effects on male reproductive hormones, semen parameters and metabolic outcomes [3].
The researchers’ explicit caveat: the reproductive benefits are likely indirect, and GLP-1 drugs have not been evaluated as treatments for male infertility or hypogonadism [10].
Can a GLP-1 replace testosterone replacement therapy for low T caused by obesity?
That question is being studied, but there is no approved GLP-1 or dual incretin agent for hypogonadism or male infertility [10].
A network meta-analysis on “treatment strategies for functional hypogonadism in obese men” was published in The Journal of Sexual Medicine in 2026 [4]. Its results are not summarized here. As noted above, the ENDO 2026 review found that men with obesity and weight-related low testosterone did better overall on liraglutide than with testosterone replacement alone [10].
Pratibha Natesh, the team lead at Warwick Medical School, said the work supports a shift away from prescribing testosterone replacement in men with obesity and low testosterone, and toward treating the underlying cause — excess weight and poor metabolic health — which can naturally restore hormone levels and preserve fertility [10]. She also stressed that the number of studies is small, results vary, and larger, better-designed trials are needed [10].
What happened when researchers added testosterone to tirzepatide?
A small pilot study from Magna Græcia University of Catanzaro, published in Minerva Endocrinology in June 2026, tested the combination in a very specific group: 10 obese men, aged 35 to 44, with a BMI of 35.8±2.1 kg/m², functional secondary hypogonadism, and a “late responder” pattern — at least 3 months on tirzepatide with less than 5% total body weight loss [5].
Five men stayed on tirzepatide alone (group A); five added testosterone undecanoate 1000 mg by injection (group B). All were reassessed at 6 months [5].
| Measure at 6 months | Tirzepatide alone | Tirzepatide + testosterone |
|---|---|---|
| Lean body mass | 63.4±3.0 kg | 66.1±3.1 kg (P<0.01) |
| HOMA-IR (insulin resistance) | 3.8±0.7 | 2.9±0.6 (P<0.01) |
| IIEF-5 (erectile function score) | 18.0±1.5 | 23.2±2.1 (P<0.001) |
Group B had greater body weight and fat mass reduction than group A (P<0.05). While group A had progressive lean body mass loss, group B recovered it. Group B’s physical activity levels nearly doubled (P<0.001) [5].
The authors themselves call these findings “preliminary.” With 10 men total, five per group, this is a pilot study — not a treatment protocol and not evidence that men should stack testosterone onto tirzepatide [5].
Do GLP-1 drugs cause erectile dysfunction or protect against it?
A large records study found tirzepatide was associated with a lower risk of erectile dysfunction in men with type 2 diabetes compared with several other diabetes drugs [7].
The study, published in the Journal of Diabetes and its Complications in 2025, used the TriNetX Global Collaborative Network — roughly 100 million patients across 100 healthcare organizations — from May 13, 2022 to May 17, 2025. It looked at men aged 18 to 70 with type 2 diabetes and no prior ED, in three 1:1 propensity-score-matched comparisons. The outcome was an ED diagnosis or a prescription for a PDE-5 inhibitor [7].
| Comparison | Risk ratio (95% CI) |
|---|---|
| Tirzepatide vs. sitagliptin | 0.70 (0.64–0.76) — about 30% lower risk |
| Tirzepatide vs. injectable semaglutide | 0.67 (0.62–0.72) |
| Tirzepatide vs. dulaglutide | 0.55 (0.51–0.59) |
All comparisons were statistically significant (p<0.001) [7]. For context, ED affects up to 60% of men with type 2 diabetes and is frequently underdiagnosed and underreported [7].
The authors say randomized trials are needed to confirm the findings and that the mechanisms are unknown. They note tirzepatide’s broader metabolic effects — including documented benefits across the SURMOUNT and SURPASS programs on metabolic outcomes, fatty liver disease and slowing kidney function decline — may contribute via vascular or neurohormonal pathways [7]. A narrative review in Sexual Medicine Reviews also covers GLP-1 receptor agonists and sexual function in both women and men, framing the evidence as emerging and in need of further research [9].
What does the FDA adverse-event database show about libido, erections and orgasm?
A cross-sectional analysis of the FDA Adverse Event Reporting System (FAERS), published in the International Journal of Impotence Research, looked at reports from Q4 2003 through Q1 2024 using the OpenVigil 2.1 platform. It covered tirzepatide, semaglutide, dulaglutide, exenatide, lixisenatide and liraglutide [8].
After removing duplicates, the analysis identified 182 male cases of orgasmic dysfunction, erectile dysfunction or decreased libido. Patients were predominantly aged 40 to 60. Exenatide accounted for 24.2% of reports and semaglutide 21.4%; diabetes was the most common indication at 43.9% [8].
The disproportionality measures were low: a reporting odds ratio (ROR) of 0.41 (95% CI 0.36–0.48), a proportional reporting ratio of 0.41 (0.36–0.48) and a relative reporting ratio of 0.42 (0.36–0.48), with chi-squared P<0.0001. The authors’ read: a weak association, with overall patient risk remaining low, though monitoring is warranted as GLP-1 use expands [8].
Two things to understand about these numbers. First, FAERS is a voluntary reporting system — the ROR is a disproportionality measure, not an incidence rate and not a demonstration of cause or protection. Second, the paper references animal data in which exendin-4 reduced sexual interaction behaviors in a brain site-specific manner in sexually naive male mice (Vestlund & Jerlhag, Hormones and Behavior, 2020) — a signal researchers keep an eye on, not a finding about men [8].
Do these drugs affect sperm or trying to conceive?
The available trial evidence found no harm. The ENDO 2026 review, presented at the Endocrine Society’s annual meeting in Chicago and described in a June 13, 2026 press release, concluded GLP-1 drugs showed no negative impact on hormones, sexual function or sperm quality after long-term use [10]. Within that review, a 24-week semaglutide study found improvements in sperm shape and cholesterol, with testosterone and hormone levels stable [10].
A systematic review in The Journal of Sexual Medicine also covers semen parameters alongside reproductive hormones and metabolic outcomes for men on GLP-1 receptor agonists [3].
The limits are clear, though. The possible testosterone benefit appears limited to men whose low testosterone is obesity-driven. GLP-1 drugs are not approved for male infertility, and the benefits researchers describe are largely indirect. The ENDO 2026 team emphasized that GLP-1s have not been evaluated as treatments for male infertility or hypogonadism [10].
How much muscle do men lose — and does lifting weights help?
A narrative review in Diabetes Care (2024) by researchers at the University of Western Australia notes that liraglutide, semaglutide, tirzepatide and retatrutide induce roughly 15–24% weight loss in adults with overweight and obesity, alongside benefits for blood pressure, cholesterol, blood glucose and insulin. But the same agents also cause rapid and significant loss of lean mass [11].
The review’s central argument is that resistance exercise is the way to preserve muscle during incretin-based weight loss [11]. A systematic review and meta-analysis of GLP-1 receptor agonists and musculoskeletal outcomes, published in the journal Drugs on September 12, 2026 as open access, also examines this territory [12]. A further review in the British Journal of Pharmacology by Prokopidis and colleagues is titled “Glucagon-like peptide-1 receptor agonists and muscle strength changes in older adults: Risks beyond muscle mass reductions” — its focus is muscle strength in older adults rather than muscle mass alone [13].
The tirzepatide-plus-testosterone pilot offers one data point on lean mass: the five men on tirzepatide alone had progressive lean body mass loss over 6 months, while the five who added testosterone recovered it (66.1±3.1 kg vs. 63.4±3.0 kg, P<0.01) and nearly doubled their physical activity (P<0.001) [5]. Again, that is 10 men, not a treatment strategy.
What’s on the label, and what should a man ask his clinician?
Zepbound (tirzepatide) is an injection for subcutaneous use, with an initial U.S. approval in 2022; the full prescribing information is available from Lilly [16]. Tirzepatide is a GLP-1 receptor agonist and GIP dual agonist with high glycemic and weight-loss efficacy; its cardiovascular outcomes trial was ongoing as of 2025 [7].
No GLP-1 or dual incretin agent has been evaluated or approved as a treatment for hypogonadism or male infertility [10]. So the practical questions for a clinician are things like: whether low testosterone might be weight-related before starting any replacement; how to preserve muscle during weight loss, including resistance exercise; and what to make of any sexual side effects while on the drug. Decisions about starting, stopping or combining treatments belong with a clinician, not with the early evidence summarized here [10][11].
Sources
- Diabetes (American Diabetes Association). 1711-P: Menopausal hormonal status and estradiol use modulate semaglutide-associated weight loss in women: analyses from STEP1 and SELECT. June 2026.
- Pharmaceuticals (MDPI). Effects of incretin-based therapies on testosterone levels and incretin response in men with hypogonadism: a systematic literature review following PRISMA 2020 guidelines.
- The Journal of Sexual Medicine. Effects of glucagon-like peptide-1 receptor agonists on male reproductive hormones, semen parameters, and metabolic outcomes: a systematic review. January 7, 2026.
- The Journal of Sexual Medicine. Treatment strategies for functional hypogonadism in obese men: a systematic review and network meta-analysis.
- Minerva Endocrinology. Effects of testosterone undecanoate as add-on therapy in obese hypogonadal men that are late responders to tirzepatide: a pilot study. June 2026.
- Nature Portfolio journal. Research article on GLP-1 receptor agonists and sexual health.
- Journal of Diabetes and Its Complications. Association of tirzepatide with erectile dysfunction in people with type 2 diabetes. October 2025.
- International Journal of Impotence Research. Male sexual dysfunction associated with GLP-1 receptor agonists: a cross-sectional analysis of FAERS data.
- Sexual Medicine Reviews. GLP-1 receptor agonists and sexual function in women and men: a narrative review of emerging evidence and the need for further research. January 5, 2026.
- Endocrine Society. Clinical trials suggest GLP-1s may improve fertility in men with obesity. June 13, 2026.
- Diabetes Care (American Diabetes Association). Incretin-based weight loss pharmacotherapy: can resistance exercise optimize changes in body composition? October 2024.
- Drugs. GLP-1 receptor agonists and musculoskeletal outcomes: a systematic literature review and meta-analysis. September 12, 2026.
- British Journal of Pharmacology. Glucagon-like peptide-1 receptor agonists and muscle strength changes in older adults: risks beyond muscle mass reductions.
- Annals of Epidemiology. GLP-1 receptor agonist medications for weight loss: sociodemographic patterns of awareness, use, and access in a U.S. national cohort. October 2026.
- Pharmacy (MDPI). Factors and disparities influencing sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists initiation in the United States: a scoping review of evidence.
- Eli Lilly and Company. ZEPBOUND (tirzepatide) injection, for subcutaneous use: prescribing information. Initial U.S. approval 2022.
Frequently asked questions
Do men lose less weight than women on semaglutide?
Yes, on average. Post hoc analyses indicate women achieve about 40% greater weight-loss reductions than men on GLP-1 receptor agonists, based on pooled data from STEP 1 (n=1,482) and SELECT (n=17,604). The difference was not fully explained by drug exposure, and men showed consistent weight loss across ages 45 to 90 in SELECT.
Can a GLP-1 replace testosterone replacement for low T caused by obesity?
Possibly, but nothing is approved for this. In a 16-week liraglutide study, men with obesity-related low testosterone saw testosterone rise, with better overall outcomes than testosterone replacement alone. The lead researcher supports treating the underlying weight and metabolic health first, but stresses the studies are small and GLP-1s are not evaluated treatments for hypogonadism.
Do GLP-1 drugs cause erectile dysfunction?
A retrospective cohort study in a large records network found the opposite. In men with type 2 diabetes, tirzepatide was associated with a lower risk of ED versus sitagliptin (RR 0.70), injectable semaglutide (RR 0.67) and dulaglutide (RR 0.55), all p<0.001. The authors note randomized trials are needed to confirm this and that mechanisms are unknown.
Did tirzepatide and semaglutide show different ED rates in diabetes?
In one records study, men with type 2 diabetes on tirzepatide had a lower rate of ED diagnosis or PDE-5 inhibitor prescription than those on injectable semaglutide (RR 0.67, 95% CI 0.62–0.72). This is an observed association from a retrospective cohort, not a randomized head-to-head comparison, and the authors call for randomized trials to confirm it.
Do these drugs affect sperm or trying to conceive?
The available trial evidence found no negative impact on sperm quality after long-term use. A 24-week semaglutide study showed improved sperm shape with stable hormone levels. However, GLP-1s are not approved for male infertility, benefits are described as largely indirect, and larger studies are still needed.
How much muscle do men lose on these drugs?
GLP-1 drugs induce roughly 15–24% total weight loss, but also cause rapid and significant loss of lean mass, according to a Diabetes Care review. The review's central argument is that resistance exercise during incretin-based weight loss is the way to preserve muscle.
Do sexual side effects show up in FDA adverse-event data?
A FAERS analysis from Q4 2003 to Q1 2024 found 182 male reports of orgasmic dysfunction, ED or decreased libido across six GLP-1 drugs. The disproportionality signal was weak (ROR 0.41, 95% CI 0.36–0.48), and the authors concluded overall patient risk remains low, though monitoring is warranted.
Is adding testosterone to tirzepatide a real treatment strategy?
Not yet. A 10-man pilot study found the combination improved lean mass, insulin resistance and erectile function scores (IIEF-5 23.2 vs. 18.0, P<0.001) in hypogonadal "late responders." The authors call the findings preliminary, and it is far too small to establish a treatment protocol.
This article summarizes FDA labeling, published research and company information current as of September 14, 2026. It is not medical advice and does not replace a conversation with your own healthcare provider. How we research and verify.