GLP-1 Medications and Sexual Function: What the Research Shows
GLP-1 drugs improve testosterone and erectile function in some men with obesity, but a FAERS signal and clinical reviews flag reduced libido. Here is what the 2025-2026 evidence actually shows.
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Reviewed by Dr. James Chen, MD, PhD, FACE on May 16, 2026
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When patients ask whether Ozempic, Wegovy, or Mounjaro will affect their sex life, the honest answer in 2026 is: it depends on which axis you measure. The clinical data on GLP-1 receptor agonists and sexual function look almost contradictory at first reading. Randomized trials show that semaglutide raises testosterone and reverses functional hypogonadism in men with obesity and type 2 diabetes. The same drug class has a pharmacovigilance signal for erectile dysfunction, anorgasmia, and reduced libido in the FDA's adverse-event database. Surveys of real-world users find roughly equal numbers reporting that desire went up and went down.
The mechanism is multi-layered: weight loss, hormonal shifts, central reward signaling, and partner dynamics all change at the same time. Pulling them apart requires looking at each line of evidence on its own terms.
Here is what the 2025-2026 research actually shows about GLP-1 medications and sexual function.
The Hormonal Case: Semaglutide Restores Testosterone in Men With Obesity
The strongest controlled evidence comes from male endocrinology. Functional hypogonadism — low testosterone driven by obesity rather than primary testicular failure — is common in men with a BMI above 35 and type 2 diabetes. Losing weight reliably restores testosterone, and GLP-1 drugs deliver weight loss as well as any non-surgical intervention available.
A 2025 randomized open-label trial published in Diabetes, Obesity and Metabolism compared semaglutide 1 mg/week to intramuscular testosterone undecanoate over 24 weeks in 25 men (median age 50, median BMI 35.9) with type 2 diabetes and functional hypogonadism. Both arms raised total testosterone and improved the Aging Males' Symptoms scale, but the semaglutide arm did something testosterone replacement therapy cannot do — it preserved fertility.
Evidence: "Semaglutide markedly improved sperm morphology, total testosterone levels and symptoms of hypogonadism. In the semaglutide group, morphologically normal sperm increased from 2% [2; 3.5] to 4% [2; 5.5] (p = 0.012), whereas sperm concentration and total number decreased significantly in the testosterone replacement therapy group." — Gregorič N, et al. Diabetes Obes Metab. 2025;27(2). DOI: 10.1111/dom.16042
A 2025 systematic review and meta-analysis in men with overweight or obesity reached the same conclusion at the class level. GLP-1 receptor agonists raised total testosterone, luteinizing hormone, and follicle-stimulating hormone, alongside reductions in body weight, waist circumference, and HbA1c. The endocrine improvements tracked with the metabolic improvements, consistent with the well-established physiology in which adipose-tissue aromatase drives testosterone-to-estradiol conversion and central HPG-axis suppression.
What the meta-analysis did not find was a consistent improvement in the International Index of Erectile Function (IIEF) score. In the Gregorič trial, only the testosterone-replacement arm showed a significant IIEF-15 improvement at 24 weeks; the semaglutide arm did not, despite the hormonal gains. That gap is the first hint that hormonal correction and clinical sexual function are not the same endpoint.
The Erectile Function Signal: Mixed and Time-Dependent
Erectile dysfunction (ED) and obesity travel together. Vascular endothelial dysfunction, chronic inflammation, and low testosterone all worsen as BMI rises, and all three improve with weight loss. The expected directional effect of a GLP-1 receptor agonist on ED is therefore positive — and several lines of evidence support that.
A 2025 narrative review in the International Journal of Impotence Research and related literature summarized animal and human data showing that GLP-1 receptor agonists improve endothelial nitric oxide signaling in penile tissue, reduce oxidative stress, and correct the metabolic abnormalities that cause vasculogenic ED. Smaller clinical cohorts in men with diabetes and obesity have reported IIEF-5 score improvements after 3-12 months of liraglutide or semaglutide therapy, in parallel with weight loss and glycemic control.
Evidence: "GLP-1 receptor agonists may exert beneficial effects on erectile function through metabolic, vascular, and endocrine mechanisms, including improved endothelial nitric oxide bioavailability, reduced oxidative stress, weight loss, and partial restoration of testosterone in men with functional hypogonadism." — Casu A, et al. Int J Impot Res. 2025. PubMed: 41008590
The counter-evidence comes from pharmacovigilance. A 2025 cross-sectional analysis of the FDA Adverse Event Reporting System (FAERS) identified 182 male sexual adverse events linked to GLP-1 receptor agonists between 2005 and the cut-off date. The reports were not limited to ED — they included reduced libido, ejaculatory dysfunction, and anorgasmia. Exenatide (24.2%) and semaglutide (21.4%) were the most frequently implicated agents.
Evidence: "We identified 182 male sexual adverse events associated with GLP-1 receptor agonists, including erectile dysfunction, libido decreased, and orgasm abnormal. The disproportionality signal was statistically significant (p < 0.0001), though signal strength was weak, and FAERS data cannot establish causality." — Barbonetti A, et al. Int J Impot Res. 2025. PubMed: 40240532
FAERS data carry well-known limitations: voluntary reporting, no denominator, indication confounding, and notoriety bias once a class becomes a media story. The signal is real but weak, and it sits next to mechanistic data and small-cohort studies pointing the other way. The most defensible reading in 2026 is that GLP-1 medications generally improve erectile function in men who lose substantial weight, but a subset of patients experience a sexual side-effect profile that has not yet been quantified by a randomized trial.
Female Sexual Function and Libido: The Less-Studied Half
The female-side data are thinner and more recent. There is no STEP secondary-endpoint paper on Female Sexual Function Index (FSFI) scores in women receiving semaglutide. Most of what is published is observational, survey-based, or framed inside biopsychosocial reviews.
A 2025 clinical review in Reproductive Endocrinology and Sexual Function introduced a biopsychosocial framework to explain a pattern that had been puzzling clinicians: weight loss should, on average, improve body image and partner dynamics, and yet a meaningful minority of women on GLP-1 therapy describe reduced sexual desire. The authors argued that GLP-1 receptor agonism in the mesolimbic dopamine system — the same circuit that drives the "food noise" reduction patients describe — also dampens other reward-driven appetites, including sexual desire.
Evidence: "Although improvements in body image and metabolic health would be expected to correlate with heightened sexual function, emerging evidence suggests GLP-1 receptor agonism may directly attenuate hedonic and reward-driven appetites, including libido, in a subset of patients. This effect is under-recognized because clinicians do not routinely screen for it." — Aluri J, et al. Reprod Endocrinol Sexual Function. 2025. DOI: 10.1016/j.resf.2025.100147
A 2025 Kinsey Institute survey of more than 2,000 adults using GLP-1 medications found bidirectional changes: 18% reported increased sexual desire and 16% reported a decrease, with the remainder unchanged. The split is consistent with what randomized data in GLP-1 and mental health and GLP-1 and food noise already show — these drugs blunt reward signaling, and for some patients that blunting is the desired effect, while for others it crosses into anhedonia.
For women in perimenopause and menopause — a population overrepresented in GLP-1 prescribing — the picture is further complicated by independent declines in estrogen and androgen output. Discussed in more depth in our analysis of GLP-1 medications and menopause, the timing of GLP-1 initiation often coincides with hormonal shifts that affect libido on their own.
What Is Actually Driving the Changes
Pulling the signals together, four mechanisms plausibly operate at once:
| Mechanism | Direction of Effect | Strength of Evidence |
|---|---|---|
| Weight loss → testosterone recovery (men) | Positive | RCT (Gregorič 2025), meta-analysis |
| Weight loss → endothelial / vascular improvement | Positive (men) | Mechanistic + small cohorts |
| Central GLP-1 agonism → reward attenuation | Negative (desire) | FAERS + clinical reviews |
| Caloric deficit + dehydration + nausea | Negative (acute) | Inferred from STEP/SURMOUNT AE profiles |
Two of these mechanisms favor improved function; two favor reduced desire. Which dominates in a given patient depends on baseline sex hormone status, baseline sexual function, the magnitude and pace of weight loss, partner-level factors, and individual sensitivity to central reward modulation.
This also explains the apparent contradiction between RCTs and pharmacovigilance. Trials measure aggregate effects on hormones and on physical function and tend to show benefit. Adverse-event databases capture qualitative complaints about desire and orgasm — endpoints that randomized trials of obesity drugs have historically not measured.
What Clinicians Should Be Doing in 2026
The 2025 International Journal of Sexual Medicine protocol paper argued for routine sexual-health screening before and during GLP-1 therapy, using validated instruments such as the IIEF-5 for men and the FSFI for women. The protocol is straightforward: baseline assessment, repeat assessment at 3, 6, and 12 months, and dose adjustment or co-therapy when scores drop.
Practical implications for patients starting a GLP-1 agonist:
- Men with obesity and suspected hypogonadism should have a baseline morning total testosterone before starting therapy. Many will not need lifelong testosterone replacement if weight loss is sustained.
- Men with established vasculogenic ED should expect gradual improvement over 6-12 months alongside weight loss, not an immediate effect.
- Patients of any sex who notice a decline in libido after initiation should report it. Dose reduction, slower titration, or temporary discontinuation are reasonable strategies, and the literature does not support assuming the effect is psychological.
- Couples should be counseled that rapid weight loss changes body composition, partner dynamics, and frequency of intercourse for reasons that have nothing to do with the drug itself.
Conclusion
GLP-1 receptor agonists improve hormonal and vascular substrates of sexual function in men with obesity, particularly those with functional hypogonadism, and there is now randomized evidence that semaglutide raises testosterone and improves sperm morphology while testosterone replacement does the opposite for fertility. At the same time, a pharmacovigilance signal and a growing clinical-review literature point to a meaningful minority of patients — both men and women — who experience reduced libido, anorgasmia, or other sexual side effects that are most parsimoniously explained by central reward attenuation.
The next chapter of this research needs randomized trials that prespecify FSFI and IIEF endpoints, stratified by sex, baseline BMI, and weight-loss magnitude. Until those data exist, the right clinical posture in 2026 is to ask the question routinely, document the answer, and treat patient-reported sexual side effects as real findings rather than incidental complaints.
References
- Gregorič N, et al. Semaglutide improved sperm morphology in obese men with type 2 diabetes mellitus and functional hypogonadism. Diabetes Obes Metab. 2025;27(2). DOI: 10.1111/dom.16042
- Barbonetti A, et al. Male sexual dysfunction associated with GLP-1 receptor agonists: a cross-sectional analysis of FAERS data. Int J Impot Res. 2025. PubMed: 40240532
- Casu A, et al. The impact of glucagon-like peptide-1 receptor agonists on erectile function: friend or foe? Int J Impot Res. 2025. PubMed: 41008590
- Aluri J, et al. Clinical review of how glucagon-like peptide-1 agonist obesity medications decrease sexual desire, and a biopsychosocial model for why we don't 'see' it. Reprod Endocrinol Sexual Function. 2025. DOI: 10.1016/j.resf.2025.100147
- A protocol for evaluation of sexual side effects of GLP-1 inhibitor medications. J Sex Med. 2025;22(Supplement_1):qdaf068.082. DOI: 10.1093/jsxmed/qdaf068.082
Last updated: 2026-05-16 Medical review: Dr. James Chen, MD, PhD, FACE
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Written By
Dr. Sarah Mitchell
Medical Director, MD, FACP
Dr. Sarah Mitchell is a board-certified internist specializing in metabolic medicine and weight management. With over 15 years of clinical experience, she has helped thousands of patients achieve sustainable weight loss through evidence-based approaches.
Medical Reviewer
Dr. James Chen
Endocrinologist, MD, PhD, FACE
Dr. James Chen is a fellowship-trained endocrinologist with expertise in diabetes, metabolism, and hormone-related weight disorders. His research on GLP-1 receptor agonists has been published in leading medical journals.
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