# Do GLP-1 Drugs Affect Fertility? 25 Men, and No Trial Measured Pregnancy Do GLP-1 drugs affect fertility? A 25-man randomized trial, a 1,899-man network, a pair-fed rat study and 176 women in PCOS | what each design can support. Publisher: This GLP Editorial Team Canonical: https://thisglp.com/research/do-glp1-drugs-affect-fertility Updated: 2026-09-17 Published: 2026-09-16 [← Research](https://thisglp.com/research) Evidence # Do GLP-1 Drugs Affect Fertility? 25 Men, and No Trial Measured Pregnancy The only randomized comparison in men enrolled 25 people and moved normal sperm morphology from 2% to 4%. In women the pooled trial evidence is 176 participants, none of them followed to conception. [This GLP Editorial Team](https://thisglp.com/about)September 20269 min readUpdated September 2026 Morphologically normal sperm, median · 2% · baseline · 4% · 24 weeks · both values sit below · the reference range · 25 men, open-label, 24 weeks **Research, not medical advice.** This GLP is independent and educational. Nothing here is a substitute for individualized care from a licensed clinician, and reading it creates no doctor–patient relationship. Talk to your own provider before starting, stopping, or changing any medication, peptide, or therapy. See our [methodology](https://thisglp.com/methodology) and [terms](https://thisglp.com/terms). Almost nobody has studied it. The only randomized comparison in men enrolled 25 people, split two ways, and ran 24 weeks [\[1\]](https://thisglp.com/research/do-glp1-drugs-affect-fertility#ref-1). On semaglutide the median proportion of morphologically normal sperm rose from 2% to 4%. Both figures sit below the reference range. In women the pooled randomized evidence is [four trials and 176 participants](https://thisglp.com/research/glp1-pcos-insulin-resistance), all in PCOS, and no trial has measured conception [\[4\]](https://thisglp.com/research/do-glp1-drugs-affect-fertility#ref-4). Nobody on this roster sells anything for fertility. ## Key takeaways - A randomized open-label trial gave 25 men either semaglutide 1 mg weekly or testosterone replacement for 24 weeks. - On semaglutide, median morphologically normal sperm rose from 2% to 4%, p=0.012. Both numbers are below the reference range. - On testosterone, sperm concentration and total count fell significantly — which is what testosterone replacement does. - So the drug beat a comparator that suppresses sperm production. That is a lower bar than it sounds. - A 23-trial network of 1,899 men does not list a GLP-1 among the strategies shown to raise testosterone. - In women, four trials and 176 participants in PCOS. No pooled trial has measured pregnancy or live birth. Men with obesity and type 2 diabetes often have low testosterone, and the standard fix is to give them testosterone. That fix has a known cost: it suppresses the hormonal signal that tells the testes to make sperm. A man who wants both the symptom relief and the fertility is stuck. This trial asked whether a weight-loss drug could be the way out. ## The trial in men Twenty-five men with type 2 diabetes, obesity and functional hypogonadism were randomized. One arm took semaglutide 1 mg a week. The other took intramuscular testosterone undecanoate 1000 mg every ten to twelve weeks. It ran 24 weeks, open-label. Median age was 50 and median BMI 35.9. Semen analysis and hypogonadism measures were taken at baseline and at the end. Baseline semen quality was poor in both arms, below the 5th percentile of reference values. That matters for reading everything that follows. These were not men with normal parameters. ## What changed In the semaglutide arm, the median proportion of morphologically normal sperm rose from 2% to 4%, p=0.012. In the testosterone arm, sperm concentration and total sperm number both fell significantly. Head to head at 24 weeks, the semaglutide group had significantly more morphologically normal sperm, higher concentration and a higher total count. Both arms saw total testosterone rise and both improved on the Aging Symptoms scale. Only the testosterone arm improved significantly on erectile function. Read the comparator before the result Testosterone replacement lowers sperm production. That is established, expected, and the reason fertility specialists avoid it in men who want children. A trial showing semaglutide produces better semen parameters than testosterone is showing something real. It is not showing that semaglutide improves fertility. Half of that gap was created by the comparator going down. ## What the numbers actually say The within-arm change on semaglutide is the part that stands on its own, and it is small. A median of 2% morphologically normal sperm became 4%. Doubling sounds substantial. Two percentage points is a different impression of the same fact. Both numbers sit below the reference range. Twenty-five men, split two ways, is twelve or thirteen per arm. Open-label means everyone knew which drug they were on, and the two regimens are impossible to confuse. The design could not have blinded this. A placebo arm would settle it, and there was not one. Those are the same questions worth asking of [any small uncontrolled study](https://thisglp.com/research/do-glp1-drugs-help-hidradenitis-suppurativa), and here at least there was randomization and a comparator. ## Where a GLP-1 sits among the alternatives A network meta-analysis pooled 23 randomized trials covering 1,899 men with obesity-related low testosterone, searched to April 2026 [\[2\]](https://thisglp.com/research/do-glp1-drugs-affect-fertility#ref-2). GLP-1-based therapy was one of the five interventions in that network. It does not appear among the results the abstract reports as significant, and the abstract gives no estimate for it either way. Testosterone replacement plus structured lifestyle therapy raised total testosterone most, MD 7.19 (95% CI 1.18 to 13.21). It was also the only strategy that significantly improved erectile function. No intervention significantly reduced glycated hemoglobin. The full comparison is in [the low testosterone network](https://thisglp.com/research/do-glp1-drugs-raise-testosterone). ## What the animal work separates Every human study here runs into the same confound: the people taking the drug are also losing weight. A rat study used a pair-fed control to break that apart [\[3\]](https://thisglp.com/research/do-glp1-drugs-affect-fertility#ref-3). One group was fed exactly what the treated group chose to eat. In male rats, both the drug and the matched restriction improved sperm motility, which points at the weight rather than the molecule. Restriction lowered androgens and semaglutide blunted that fall. In females, progesterone, pregnenolone and estradiol fell in a way the diet alone did not produce. Nobody measured whether any animal conceived, and four weeks in a rodent is not a year in a person. The design and its limits are in [the pair-fed rat study](https://thisglp.com/research/semaglutide-reproduction-pair-fed-rats). ## The evidence in women Four randomized trials, 176 participants in total, pooled for women with PCOS and obesity [\[4\]](https://thisglp.com/research/do-glp1-drugs-affect-fertility#ref-4). Waist circumference fell 5.16 cm and BMI 2.42 points. Total testosterone fell 1.33 (95% CI −2.55 to −0.12). HOMA-IR, the marker closest to the reason these drugs are supposed to help PCOS, did not move significantly. No pregnancy or live-birth outcome was pooled. Weight loss genuinely helps many PCOS symptoms, and that does not require this literature. What the trials do not establish is that the drug treats the underlying endocrinology. That reading is set out in [the PCOS pooled analysis](https://thisglp.com/research/glp1-pcos-insulin-resistance). ## What a buyer should do with this Nothing on this roster is sold for fertility, and no seller claims it. If fertility is the actual goal, that is a reproductive endocrinologist’s question and semen analysis is the measurement. What this trial supports is narrower. A man is already facing a choice between these two treatments. The semen parameters point one way and the erectile function score points the other. The broader sexual-function evidence is thin and [covered separately](https://thisglp.com/research/do-glp1-drugs-affect-sex-drive). What sellers say about any of it is close to nothing, which [the census of silence](https://thisglp.com/tools/questions-they-leave-open) counts directly. ## Frequently asked Do GLP-1 drugs affect fertility? Almost nobody has studied it directly. The only randomized comparison in men enrolled 25 people and moved median normal sperm morphology from 2% to 4%. No trial in either sex has measured pregnancy or live birth. Does semaglutide improve sperm? In that trial it beat testosterone replacement, which suppresses sperm production. The within-arm change was two percentage points, from one figure below the reference range to another below it. Do these drugs raise testosterone? A network of 23 trials and 1,899 men does not list a GLP-1 among the strategies shown to raise it. The abstract gives no estimate for the GLP-1 arm either way. Do they help PCOS? Four trials and 176 participants found waist, BMI and total testosterone fell. HOMA-IR, the insulin-resistance marker the mechanism story rests on, did not move significantly. Can I buy one for fertility? No seller on this roster offers a fertility service or claims the indication. Semen analysis and a reproductive endocrinologist are the measurement here, not a weight-loss intake form. ## Sources 1. \[1\] Gregorič N, et al. (2025). Semaglutide improved sperm morphology in obese men with type 2 diabetes mellitus and functional hypogonadism Diabetes, Obesity and Metabolism. [PMID 39511836](https://pubmed.ncbi.nlm.nih.gov/39511836/) 2. \[2\] Yang L, et al. (2026). Treatment strategies for functional hypogonadism in obese men: a systematic review and network meta-analysis The Journal of Sexual Medicine. [PMID 42704281](https://pubmed.ncbi.nlm.nih.gov/42704281/) 3. \[3\] Sotzen MR, et al. (2026). Beyond weight loss: Disentangling the direct effects of semaglutide vs equivalent calorie restriction on reproductive systems of male and female rats Molecular Metabolism. [PMID 42692145](https://pubmed.ncbi.nlm.nih.gov/42692145/) 4. \[4\] Austregésilo de Athayde De Hollanda Morais B, et al. (2024). The efficacy and safety of GLP-1 agonists in PCOS women living with obesity in promoting weight loss and hormonal regulation: A meta-analysis of randomized controlled trials Journal of Diabetes and Its Complications. [PMID 39178623](https://pubmed.ncbi.nlm.nih.gov/39178623/) ## Where to get it ### Best GLP-1 injections Every injectable seller we can verify, with the price each one publishes and an honest read of what the trials measured. [Compare providers →](https://thisglp.com/best/compounded-semaglutide) ## More in Evidence - [ 150 minutes · Weekly activity goal · 2 days · Muscle strengthening · Adapt · Symptoms and ability ### Exercise on Ozempic: Building Strength Without Ignoring Symptoms ](https://thisglp.com/research/exercise-on-ozempic) - [ STEP 1, semaglutide 2.4 mg vs placebo, % change at 68 weeks · LDL cholesterol · −2.5% vs +1.3% · Total cholesterol · −3.3% vs +0.1% · HDL cholesterol · +5.2% vs +1.4% · Triglycerides · −21.9% vs −7.3% · Wegovy label, Table 13. Adults without diabetes. Ozempic doses are lower. ### Does Ozempic Lower Cholesterol? 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