The short answer
Mostly the same medicine, with a few honest differences. Men lose meaningful weight on semaglutide and tirzepatide, but on average a little less than women: in one prespecified semaglutide analysis, 7.2 percent more than placebo for men against 9.6 percent for women. Hair loss was rare in men, under 1 percent. The labels show no difference in how the body handles the drug by sex, and they say nothing about testosterone or erections.
Most people who write to GLP-1 SOS are women, and so were most people in the weight-loss trials. So when men ask whether these answers apply to them, the fair reply is: mostly yes, and here is exactly what has been published by sex, and where the data run out.
At a glance
Two differences, and one non-difference
1
Same drug levels
The labels report no clinically meaningful difference in drug exposure by sex.
2
A smaller average loss
Men lose less in percentage terms on average, and tend to plateau sooner.
3
Far less hair shedding
Under 1 percent of men reported hair loss in the trials, against 4 to 8 percent of women.
What the data show for men
Start with who was studied. In the main Wegovy weight-loss trial 74 percent of participants were women, and in the main Zepbound trial 68 percent. Men are better represented elsewhere: 72 percent of the Wegovy heart-outcomes trial and most of the Zepbound sleep apnea trials were men. So there is real data on men, but less of it in the weight-loss studies people quote most.
Weight comes off in both sexes. The Zepbound label states that weight fell irrespective of sex. Where results are published by sex, women lose more in percentage terms: in a prespecified analysis of the semaglutide heart-failure trials, weight fell 9.6 percent more than placebo in women and 7.2 percent in men, while symptoms improved equally. A tirzepatide analysis found that women kept losing for longer before reaching a plateau. The reasons are not settled.
Lab note
A smaller percentage is not a failed treatment. Judge your own curve, not your partner’s.
Side effects are listed the same way for everyone, and the labels do not break nausea, vomiting or constipation down by sex. Hair loss is the exception: on Wegovy 0.9 percent of men reported it against 4 percent of women, and on Zepbound 0.5 percent against 7.1 percent. The labels do not list changes in testosterone, libido or erections; our page on GLP-1 and sex drive covers what is known. Body composition looked alike by sex in a tirzepatide substudy: about three quarters of the weight lost was fat and one quarter lean mass.
Published by sex
The numbers for men
7.2% vs 9.6%
weight loss beyond placebo, men vs women, in the semaglutide heart-failure trials (JACC, 2024)
0.5% vs 7.1%
men vs women reporting hair loss on Zepbound, per the Zepbound label
About 75%
of weight lost on tirzepatide was fat, consistent across subgroups including sex (Diabetes, Obesity and Metabolism, 2025)
Sources: Journal of the American College of Cardiology, 2024; Zepbound Prescribing Information, August 2026; Diabetes, Obesity and Metabolism, 2025.
What to do
- Judge your results on your own trend. Weigh weekly and look at three months, not three weeks. Men tend to plateau sooner; a slower curve than your partner’s is expected, not a failure.
- Eat to protect muscle. The adult protein RDA works out to about 56 grams a day for a reference man, and more may suit active weight loss; ask your prescriber for your number. See how much protein to eat on a GLP-1.
- Lift something, regularly. Lean mass falls along with fat. Strength training plus enough protein is the main lever you control; our page on GLP-1 and muscle loss explains why.
- Do not guess about libido or erections. The labels do not list them, and weight change, sleep, mood and other medicines all play a part. Bring it up with your doctor and ask for a proper check rather than a supplement.
- Bring your full medicine list. If you take insulin or a sulfonylurea for diabetes, the labels warn of low blood sugar when a GLP-1 is added, and your prescriber may adjust those doses.
- Keep the gut side simple. Nausea and constipation are listed for men and women alike. A small dinner and a short walk help, and that routine is why we built GLP-1 SOS Daily Gut Relief: 250 mg of magnesium, ginger root and a 19-strain probiotic blend in 2 capsules with dinner, to support regular bowel movements and digestive comfort.*
*GLP-1 SOS Daily Gut Relief supports regular bowel movements and digestive comfort. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
Two kinds
Expected, or a same-day call
Expected, same as anyone
- Queasy days after the first shots and dose steps
- Constipation or burping in the first months
- Much smaller appetite
- Slower loss than a partner on the same drug
Call the same day
- Severe belly pain, sometimes into the back
- Vomiting, or cannot keep liquids down
- Upper-right pain, fever or yellow eyes
- A neck lump, hoarseness or trouble swallowing
The red flags are the same for men and women. So is the advice: call, do not wait.
When to call your doctor
Call your prescriber the same day if:
- You have severe belly pain that does not go away, with or without vomiting
- You vomit repeatedly or cannot keep liquids down
- You have upper-right belly pain, fever, or yellow skin or eyes
- You notice a lump or swelling in your neck, hoarseness or trouble swallowing
- You take insulin or a sulfonylurea and have shakiness, sweating or confusion
Swelling of the face or throat, or trouble breathing, is an emergency: call 911.
From the people behind the Lab
You do not have to figure this out alone.
GLP-1 SOS is the daily companion made for life on a GLP-1. Plain answers like this one, a support team that replies to real questions from real people, and daily formulas like GLP-1 SOS Daily Gut Relief, designed around the side effects that come with the medication. The GLP-1 Lab is our free education arm: no login, no paywall, no hype. Side effects are part of the road. Suffering through them is not.
Questions people also ask
Do men lose less weight on Ozempic or Wegovy?
On average, somewhat less in percentage terms. In a prespecified analysis of the semaglutide heart-failure trials, weight fell 7.2 percent more than placebo in men and 9.6 percent in women, and symptoms improved equally in both. Men still lose a clinically meaningful amount. Compare your own trend over three months, not your result against a partner’s or a friend’s.
Does Zepbound or Mounjaro lower testosterone?
The labels do not list changes in testosterone, libido or erections, so there is no label data either way. If you notice low drive, unusual tiredness or erection changes, ask your doctor for an evaluation rather than guessing; weight change, sleep, mood and other medicines can all play a part. See our page on GLP-1 and libido for what is known.
Do men get hair loss on a GLP-1?
Rarely, in the trials. Hair loss was reported by 0.9 percent of men on Wegovy and 0.5 percent of men on Zepbound, against 4 and 7.1 percent of women. When it happens it is usually temporary shedding linked to fast weight loss, not male-pattern hair loss, which follows its own course. Steady protein and slower weight loss help, and a shedding that lasts many months is worth a check.
Can a GLP-1 affect male fertility?
The labels have no human data on male fertility. In animal studies, semaglutide showed no effect on male fertility, and tirzepatide showed no effect on sperm shape, mating or fertility. The pregnancy warnings in the labels apply to the person who will carry the pregnancy. If you and a partner are planning to conceive, tell your prescriber so you can plan together.
Do men need more protein on a GLP-1?
Usually more in grams, because men are often heavier. The adult RDA is 0.8 grams per kilogram of body weight, which comes to about 56 grams a day for a reference man and 46 grams for a reference woman, and higher intakes are discussed during rapid weight loss. Ask your prescriber for your number and spread it across small meals; read GLP-1 and muscle loss for why it matters.
Sources (6)
- Wegovy (semaglutide) injection and tablets, Prescribing Information. Novo Nordisk / FDA, revised June 2026.
- Zepbound (tirzepatide) injection, Prescribing Information. Eli Lilly, revised August 2026.
- Efficacy of Semaglutide by Sex in Obesity-Related Heart Failure With Preserved Ejection Fraction: STEP-HFpEF Trials. Journal of the American College of Cardiology, 2024.
- Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study of adults with obesity or overweight. Diabetes, Obesity and Metabolism, 2025.
- Time to weight plateau with tirzepatide treatment in the SURMOUNT-1 and SURMOUNT-4 clinical trials. Clinical Obesity, 2025.
- Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press, 2005.
Reviewed by the GLP-1 SOS editorial team · Education, not medical advice · Talk to your prescriber about your dose and your symptoms.
