Low testosterone · Telehealth for men · Canada & USA
Do GLP-1 weight-loss drugs raise or lower testosterone in men?
In studies of men with overweight or obesity, testosterone usually rises. Meta-analyses of GLP-1 drugs such as semaglutide and liraglutide, plus early tirzepatide data, report higher testosterone alongside weight loss. Fast weight loss also takes some muscle with it, about a quarter of the weight lost on tirzepatide in SURMOUNT-1, so the best results come from pairing the drug with labs, protein, strength training and sleep. We review your labs before and during treatment and build the plan around you.
Part of our low testosterone and andropause guide for men in Canada and the USA.
What the research shows
Four recent systematic reviews looked at GLP-1 drugs in men. A 2026 meta-analysis in Andrology (Corona and colleagues; 8 GLP-1 studies, 375 men with overweight or obesity) found that GLP-1 drugs significantly raised total and calculated free testosterone along with LH and FSH. A 2025 Andrology meta-analysis (Salvio and colleagues; 7 studies, 680 men) found a significant rise in total testosterone, with LH, FSH, SHBG and free testosterone rising too, and larger weight loss went with a larger rise. A 2026 Journal of Sexual Medicine review (Deameh and colleagues; 10 studies, 639 men) found total testosterone consistently higher, with LH and FSH preserved or raised and free testosterone changes inconsistent. A 2025 BMC Urology meta-analysis (Orra and colleagues; 4 studies, 219 men) found bioavailable testosterone higher.
Higher in all four
Total or bioavailable testosterone rose after GLP-1 treatment in each of the four reviews.
The brain’s signal held up
LH and FSH were preserved or raised, while the testosterone-therapy comparison groups in the Deameh review showed suppression. See our TRT and fertility guide.
Free testosterone varies
Free testosterone rose in the Corona and Salvio analyses, was unchanged in the Orra review and varied in the Deameh review, where SHBG often rose at the same time.
Your numbers are the answer
Averages hide a wide range, so we compare your own labs before and during treatment.
Why it rises: weight loss, and possibly more
Weight loss is the best-established route. A 2013 meta-analysis of 24 studies (Corona and colleagues) found that total testosterone rose by about 2.9 nmol/L after low-calorie diets and about 8.7 nmol/L after bariatric surgery. A 2026 systematic review of incretin drugs (La Vignera and Condorelli) reported average total testosterone rises of 2.5 to 5.2 nmol/L with semaglutide, liraglutide and tirzepatide in men with obesity-related low testosterone, largely tied to weight loss and better insulin sensitivity. The 2026 Corona meta-analysis found the rises independent of weight loss and suggests a direct effect on the hypothalamus-pituitary-testis axis. The reviews agree on the direction, and research on the mechanism continues.
Weight comes off
In the Salvio meta-analysis, larger percent weight loss went with a larger testosterone rise.
Insulin sensitivity improves
The La Vignera review links the testosterone rise to better insulin sensitivity as well as weight loss.
A possible direct effect
The 2026 Corona analysis points to the brain-to-testes axis itself, a question that new trials can settle.
What we do with this
We check LH, SHBG and free testosterone before you start, so any change has a baseline to measure against.
Real-world numbers and a tirzepatide pilot
A retrospective chart review presented at ENDO 2025 (Portillo Canales, Dhindsa and colleagues) followed 110 men on semaglutide, dulaglutide or tirzepatide (average age 54, 86 with type 2 diabetes, about 1.6 years of therapy). Average weight fell from 116 to 104 kg, total testosterone rose from 322 to 380 ng/dL, and free testosterone from 7.0 to 8.2 ng/dL. The share of men with total testosterone above 300 ng/dL rose from 53 percent to 77 percent, and more weight lost went with a bigger rise. A controlled pilot in Reproductive Biology and Endocrinology (La Vignera and colleagues, 83 men with obesity and low testosterone, aged about 55) compared tirzepatide with lifestyle change alone and with transdermal testosterone for two months. The tirzepatide group had larger rises in LH, FSH, SHBG, total, free and bioavailable testosterone, and lower estradiol.
Total testosterone
Up from 322 to 380 ng/dL on average in the ENDO 2025 chart review of 110 men.
Free testosterone
Up from 7.0 to 8.2 ng/dL in the same review, with SHBG steady at 36 and 38 nmol/L.
More men in range
The share above 300 ng/dL moved from 53 percent to 77 percent with about 10 percent weight loss.
What we do with it
These studies are short and small, which is why we follow your own labs through the whole course.
Protecting muscle while the weight comes off
Fast weight loss takes some lean mass with the fat. In a body-composition substudy of SURMOUNT-1 (160 adults, 73 percent women, DXA scans at baseline and over a 72-week trial), tirzepatide cut body weight by 21.3 percent, fat mass by 33.9 percent and lean mass by 10.9 percent, and about 75 percent of the weight lost was fat and 25 percent was lean mass. A 2025 joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society recommends baseline muscle-strength and body-composition assessment and preserving muscle and bone through resistance training and an appropriate diet. In the S-LITE trial (195 adults, one year after a low-calorie diet), exercise plus liraglutide cut body-fat percentage by 3.9 points, about twice the drop of either alone. A 2026 review in the Journal of Clinical Endocrinology & Metabolism (Friedl and colleagues) adds that severe energy deficit and disrupted sleep turn down the brain’s LH signal.
Protein at every meal
A protein target set for your size and training, with simple meal ideas for days when appetite is low.
Strength work you will keep
Resistance sessions matched to your level, with progressions we track together.
Sleep and recovery
A steady sleep schedule and recovery days that support hormones and muscle.
Body-composition check-ins
Waist, strength and how your clothes fit tracked alongside your labs. See health coaching.
Reading your labs: total, free and SHBG
SHBG tends to rise as weight falls, so total and free testosterone can move by different amounts. The 2026 Journal of Sexual Medicine review found free testosterone changes inconsistent and often offset by rising SHBG, and the authors of the ENDO 2025 chart review wrote that free testosterone measurement is essential in men with obesity because weight loss raises SHBG. A US cohort of 3,671 men tested for low testosterone found obese men averaged an SHBG of 36 nmol/L versus 50 in non-obese men (Cooper and colleagues, 2015), so SHBG earns a place on every panel. We read total testosterone, free testosterone, SHBG, LH and estradiol together with your metabolic markers. Our functional health review adds the wider picture.
Total testosterone
The full amount in the blood, free plus bound.
SHBG
The carrier protein that moves with weight, which explains many gaps between total and free.
Free testosterone
The usable share, read together with symptoms and the other labs.
LH and FSH
Show whether the brain’s signal to the testes is staying on during weight loss. See the full lab list.
How we help before, during and after GLP-1 treatment
Odin Health Labs is telehealth for men in Canada and the USA with low testosterone symptoms. Whether you are about to start a GLP-1 drug, partway through or finishing a course, we work on the labs, muscle, sleep and nutrition side. See also our guide on TRT or fixing the causes first. Here is how we work with you.
- Step 1
Review your labs before you start
Total and free testosterone, SHBG, LH, FSH, estradiol and metabolic markers, plus your weight, strength and sleep patterns, so you have a clear baseline.
- Step 2
Build a muscle-protecting plan
Protein, strength training, sleep and targeted support set up around your schedule, before the weight starts to move.
- Step 3
Re-check during weight loss
Repeat labs and regular check-ins show how testosterone, SHBG and your body are responding, and we adjust your plan with you.
- Step 4
Keep the gains
As your dose or goals change, we help you hold muscle, sleep and training habits that last.
Sources
- Corona G, Sparano C, Romeo M, Rastrelli G. Emerging effects of glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter 2 inhibitors on male sexual hormones and behaviors: systematic review and meta-analysis. Andrology 2026;14:1988-2001. doi.org/10.1111/andr.70238
- Salvio G, Ciarloni A, Ambo N, Bordoni M, et al. Effects of glucagon-like peptide 1 receptor agonists on testicular dysfunction: a systematic review and meta-analysis. Andrology 2025;13:2022-2034. doi.org/10.1111/andr.70022
- Deameh MG, Ramez M, Rowaiee R, Bani Irshid BA. Effects of glucagon-like peptide-1 receptor agonists on male reproductive hormones, semen parameters, and metabolic outcomes: a systematic review. J Sex Med 2026;23. doi.org/10.1093/jsxmed/qdaf381
- Orra SH, Martinez JVN, Porto BC, Passerotti CC. Effect of GLP-1 agonists on testosterone levels: a systematic review and meta-analysis. BMC Urol 2025;25:311. doi.org/10.1186/s12894-025-02005-0
- La Vignera S, Condorelli R. Effects of incretin-based therapies on testosterone levels and incretin response in men with hypogonadism: a systematic literature review. Pharmaceuticals (Basel) 2026;19(8):1321. doi.org/10.3390/ph19081321
- La Vignera S, Cannarella R, Garofalo V, Crafa A, et al. Short-term impact of tirzepatide on metabolic hypogonadism and body composition in patients with obesity: a controlled pilot study. Reprod Biol Endocrinol 2025;23:92. doi.org/10.1186/s12958-025-01425-9
- Portillo Canales S, Iqbal I, Akande R, Wood E, Albert SG, Dhindsa S. Effect of incretin-based weight loss drugs on testosterone concentrations in men (abstract MON-708, ENDO 2025). J Endocr Soc 2025;9(Suppl 1). doi.org/10.1210/jendso/bvaf149.1941
- Look M, Dunn JP, Kushner RF, Cao D, et al. Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study of adults with obesity or overweight. Diabetes Obes Metab 2025;27(5):2720-2729. doi.org/10.1111/dom.16275
- Mozaffarian D, Agarwal M, Aggarwal M, et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. Obesity Pillars 2025;15:100181. doi.org/10.1016/j.obpill.2025.100181
- Lundgren JR, Janus C, Jensen SBK, Juhl CR, et al. Healthy weight loss maintenance with exercise, liraglutide, or both combined. N Engl J Med 2021;384:1719-1730. doi.org/10.1056/NEJMoa2028198
- Corona G, Rastrelli G, Monami M, et al. Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis. Eur J Endocrinol 2013;168(6):829-843. doi.org/10.1530/EJE-12-0955
- Friedl KE, Nindl BC, Potter AW. Stress-associated testosterone suppression: central adaptation or hypogonadism? J Clin Endocrinol Metab 2026;111(8):e1951-e1960. doi.org/10.1210/clinem/dgag181
- Cooper LA, Page ST, Amory JK, Anawalt BD, Matsumoto AM. The association of obesity with sex hormone-binding globulin is stronger than the association with ageing. Clin Endocrinol 2015;83(6):828-833. doi.org/10.1111/cen.12768
Frequently asked questions
Do GLP-1 drugs like semaglutide and tirzepatide raise or lower testosterone in men?
In men with overweight or obesity, the research points up. A 2026 meta-analysis in Andrology (8 studies, 375 men) found that GLP-1 drugs significantly raised total and calculated free testosterone along with LH and FSH. A 2025 Andrology meta-analysis (7 studies, 680 men) and a 2026 Journal of Sexual Medicine review (10 studies, 639 men) also found higher total testosterone. A chart review of 110 men presented at ENDO 2025 saw average total testosterone climb from 322 to 380 ng/dL on semaglutide, dulaglutide or tirzepatide. Most studies are small, short and in men with obesity or diabetes, so we measure your own numbers before and during treatment and track the change with you.
Is the testosterone rise from the drug itself or from the weight loss?
Researchers read it two ways, and both agree on the direction. The 2026 Corona meta-analysis found that the testosterone rises were independent of the weight lost, which suggests a direct effect on the hypothalamus-pituitary-testis axis. A 2026 systematic review of incretin therapies (La Vignera and Condorelli) reported rises of 2.5 to 5.2 nmol/L and concluded they were largely mediated by weight loss and better insulin sensitivity. A 2025 Andrology meta-analysis found that larger percent weight loss went with a larger testosterone rise. Either way, the practical step is the same: check your baseline, then re-check as the weight comes off.
Can fast weight loss on a GLP-1 drug cost me muscle?
Some of the weight lost is lean mass, and you can plan for it. In a body-composition substudy of SURMOUNT-1 (160 adults, 73 percent women), tirzepatide cut body weight by 21.3 percent, fat mass by 33.9 percent and lean mass by 10.9 percent over a 72-week trial, and about three-quarters of the weight lost was fat and one quarter was lean mass. A 2025 joint advisory from four US obesity and nutrition societies lists muscle and bone loss among the challenges of GLP-1 treatment and recommends resistance training and an appropriate diet to preserve muscle and bone. We build your protein, strength-training, sleep and fueling plan and track how your body responds.
Why can my total testosterone rise while free testosterone barely moves?
SHBG, the protein that carries testosterone in the blood, tends to rise as weight falls, and that pulls free testosterone down relative to total. In the 2026 Journal of Sexual Medicine review, free testosterone changes were inconsistent and often offset by rising SHBG. In the ENDO 2025 chart review, the authors stressed that free testosterone should be measured in men with obesity because SHBG moves with weight loss. We read total testosterone, free testosterone and SHBG together, so you see the whole picture.
Which labs should I get before and during GLP-1 treatment?
A useful panel covers total and free testosterone, SHBG, LH, FSH and estradiol, along with metabolic markers such as A1c. LH and FSH show whether the brain’s signal to the testes is staying on, and SHBG explains gaps between total and free testosterone. Many men repeat the panel after meaningful weight change. Our lab guide explains each result in plain language, and we review your numbers with you.
How does Odin Health Labs work with my doctor?
Odin Health Labs is a telehealth service for men in Canada and the USA with low testosterone (andropause) symptoms. We work alongside whoever prescribes your GLP-1 medication: we review your labs with you, build your muscle-protection, sleep and nutrition plan, and track your progress. We can share your plan and results with your own doctor if you choose. See our low testosterone overview and our Privacy Policy.
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