Mounjaro and Ozempic for men: what's different?

Is there a weight-loss medicine just for men?

No. The GLP-1 medicines approved for weight are the same for both sexes. Their labels approve them for adults.^12,13

The US Wegovy label covers adults with obesity, or with overweight plus a weight-related health problem.¹² The US label for tirzepatide (sold in the US as Zepbound) uses the same adult wording.¹³ Tirzepatide is the medicine in Mounjaro (what is tirzepatide?).

In India, Lilly launched Mounjaro in March 2025 for long-term weight management in adults with a BMI of 30 or more, or 27 or more with a weight-related health problem, and for type 2 diabetes.²⁴ Those are label thresholds, not India's lower BMI cut-offs (below). Ozempic is semaglutide for type 2 diabetes here, at 0.25, 0.5 and 1 mg; Wegovy is the semaglutide brand for weight.²⁵ Wegovy vs Ozempic explains the difference. If GLP-1 is a new term, what GLP-1 stands for explains it.

Online "fat burner" capsules for men are a different thing. Herbal products have their own post: Ayurvedic weight-loss medicines. The older pill orlistat is compared in orlistat vs GLP-1 medicines.

Do men lose less weight on GLP-1 medicines?

On average, yes. In the semaglutide and tirzepatide weight trials, men lost a smaller share of their body weight than women did.^1,3

The STEP trials tested semaglutide 2.4 mg, the Wegovy dose. A 2023 commentary listed how much more weight people lost on it than on a dummy injection (placebo), by sex.¹

"Points" means percentage points of body weight, drug minus placebo. These are extra points over placebo; the tirzepatide numbers below are total loss from start. Source: Jensterle et al., Diabetes Therapy 2023 (a commentary citing Novo Nordisk STEP data). Checked 5 October 2026.

A STEP 1 analysis found sex was linked to the result on its own, separately from starting weight.² For a 100 kg man, 8 extra points is about 8 kg more than on placebo. For a 100 kg woman, 14 points is about 14 kg. This is our arithmetic, not a forecast.

Tirzepatide (Mounjaro). Researchers led by Eli Lilly, which makes tirzepatide, pooled the four SURMOUNT trials in a look-back presented at the EASD conference in 2024: 4,677 adults, 1,678 of them men.³ It came out as a conference abstract and press release, not a full paper.³ Women lost up to 24.6% of their weight on tirzepatide, and men up to 18.1%.³ These are the best results across the trials, measured as total loss from starting weight, not extra loss over placebo, and the release doesn't name the trial or dose.³ So they can't be set against the STEP points above. Men started heavier: 115.2 kg on average in SURMOUNT-1, vs 99.8 kg for women.³ In three of the four trials, similar shares of men and women reached 5%, 10% and 15% weight loss.³

We looked for a placebo-adjusted tirzepatide result by sex to match STEP 1. The supplementary appendix of the main SURMOUNT-1 paper has no weight result split by sex, so we found no like-for-like figure.²³ Men were about 32% of SURMOUNT-1.²³

Why the gap? Nobody knows for sure. One idea is dose: women weigh less on average, so the same dose reaches higher levels in their blood.¹ Sex hormones and slower stomach emptying in younger women have also been suggested.¹ Full trial results for everyone are in how much weight people lose on Ozempic or Mounjaro.

Men were a minority in most weight trials. They were 26.9% of people on semaglutide in STEP 1 and 19.8% in STEP 4.¹ We found no Indian trial that reported weight loss by sex.

Why does waist size matter for Indian men?

Indians tend to store fat around the belly and organs. India's 2009 consensus asks men with a waist above 90 cm (35.4 inches) to seek medical help.⁵

The consensus describes Asian Indians as carrying more belly fat, including fat inside the abdomen (visceral fat).⁵ It also notes fat stored in the liver and muscle.⁵ It sets two waist levels for men.⁵

• 78 cm (30.7 inches): avoid gaining weight and stay active.⁵
• Above 90 cm (35.4 inches): seek medical help so risk factors can be checked and managed.⁵ The level for women is 80 cm (31.5 inches).⁵

The Western cut-off for men is 102 cm (40.2 inches).⁵ The consensus found it "much less sensitive" in Indians.⁵ India's BMI cut-offs are lower too: overweight from 23 and obesity from 25.⁵ Measure just above the hip bone, standing, before eating, at the end of a normal breath out.⁵

Belly fat fell on tirzepatide in trials. In a SURMOUNT-1 body-scan substudy, waist size fell 18.1 cm (7.1 inches) on tirzepatide vs 3.4 cm (1.3 inches) on placebo.⁴ Visceral fat fell 40.1% vs 7.3%.⁴ The 160 people were 73% women, and results did not differ significantly by sex.⁴

Check your own numbers in the BMI and waist tool or Guide 1: weight and health in Indians. A short Answer is on the way: What waist size is too high for Indian men and women?.

Do GLP-1 medicines change testosterone or erections?

We found no large trial built to answer this. The evidence is small studies and health-record reviews, which can show a link but not a cause.^7,8,9,10

Testosterone. A 2025 review pooled 7 studies of 680 men with overweight or obesity.⁷ Total testosterone rose on GLP-1 medicines, and rose more with more weight lost.⁷ A 2026 review of 10 studies (639 men) found a rise too, mainly in men with obesity or type 2 diabetes.⁸ Changes in free testosterone were inconsistent.⁸

The 2025 review says current studies can't show the medicine acts on the testes directly; weight loss may explain the rise.⁷ The 2026 review is more hopeful. It says GLP-1 medicines may raise testosterone and possibly improve semen quality in men with metabolic problems, but that longer controlled studies are needed.⁸

Erections: studies point both ways. The 2025 review found erection scores rose more on GLP-1 medicines than on the other treatments they were compared with.⁷ Health records tell a different story:

• A US records study (2024) compared 3,094 men aged 18–50 without diabetes, prescribed semaglutide for weight, with similar men.⁹ New erection problems or tablets for them were recorded in 1.47% vs 0.32%.⁹ Low testosterone was diagnosed in 1.53% vs 0.80%.⁹
• A US records study (2026) followed men with type 2 diabetes.¹⁰ Erection problems were recorded at 35.2 vs 28.0 per 1,000 person-years on GLP-1 medicines vs another diabetes drug class.¹⁰ The authors say this "may reflect residual or selection bias" and does "not establish causation".¹⁰
• A look back inside a diabetes trial (REWIND) analysed a standard questionnaire from 3,725 men.¹¹ New moderate or severe erection problems were slightly less common on dulaglutide: 21.3 vs 22.0 per 100 person-years.¹¹ This was exploratory, and Eli Lilly, which makes dulaglutide, funded it.¹¹

Records studies count diagnoses and prescriptions, not what happened in each person. Obesity itself contributes to low testosterone and lower fertility in men, the 2023 commentary notes.¹

Do GLP-1 medicines affect sperm or fertility in men?

Human data are thin. A 2026 review found better semen results in men with obesity or low testosterone, and no change in healthy men.⁸

That review called for "more long-term, controlled studies" with standard fertility measures.⁸ The US labels hold only animal data for males. Semaglutide had no effect on male fertility in rats.¹² Tirzepatide had no effect on sperm shape, mating or fertility in rats.¹³

We found no instruction in either US label for men planning a child. The labels' pregnancy and contraception advice is for women.^12,13 That side is covered in GLP-1 medicines, pregnancy and the pill.

Can GLP-1 medicines help sleep apnoea?

Tirzepatide reduced breathing pauses in two sleep apnoea trials where most people were men. The US approves it for this; we found no separate Indian approval.^13,14

Obstructive sleep apnoea is disordered breathing during sleep.¹⁴ An Indian review of sleep studies found it in 13% of men vs 5% of women.¹⁵ It estimated 104 million Indians of working age have it.¹⁵

SURMOUNT-OSA was two 52-week trials in 469 adults with obesity and moderate to severe sleep apnoea.¹³ Men were 67% and 72% of the two groups.¹³ People took tirzepatide 10 or 15 mg a week, or placebo; people with type 2 diabetes were excluded.¹³ Breathing pauses (the apnoea-hypopnoea index, or AHI) are counted per hour of sleep.¹⁴

Fall in breathing pauses an hour of sleep, tirzepatide vs placebo:

In both trials, stomach effects (nausea, diarrhoea) were the most common side effects.^13,14 Eli Lilly funded the trials.¹⁴ The US label approves tirzepatide (Zepbound) for moderate to severe sleep apnoea in adults with obesity.¹³ A full post is coming: Sleep apnoea and weight-loss medicines.

Do GLP-1 medicines protect men's hearts?

In SELECT, the big heart trial of semaglutide 2.4 mg, 72% of people were men. Heart attacks, strokes and heart deaths were fewer on the medicine.^12,16

SELECT enrolled 17,604 adults aged 45 or older with heart or blood-vessel disease and a BMI of 27 or more. None had diabetes.¹⁶ Over about 3 years, 6.5% on semaglutide had a heart attack, stroke or heart death, vs 8.0% on placebo.¹⁶ That is 1.5 fewer events per 100 people, by our arithmetic. Novo Nordisk, which makes Wegovy, funded it.¹⁶

By sex, the hazard ratio (the relative drop in risk) was 0.79 in men and 0.84 in women.¹⁷ The women's range crossed 1, so their result was less certain.¹⁷ Side effects matter too: 16.6% stopped the medicine for side effects, vs 8.2% on placebo.¹⁶

At the June 2025 India launch, Novo Nordisk said Wegovy was approved here to cut major heart events.¹⁸ A deeper post is coming: Do GLP-1 medicines protect the heart?. Heart conditions and the "when not to" questions are in Guide 4: should I consider a GLP-1?

Do men lose more muscle on GLP-1 medicines?

Body scans in one tirzepatide trial found no difference by sex. A US advisory's modelling suggests muscle may be a bigger share of what men lose, without strength training.^4,6

In the SURMOUNT-1 body-scan substudy, about three-quarters of the weight lost on tirzepatide was fat in both men (73%) and women (75%), with no significant difference by sex.⁴ Only 160 people were scanned, 73% of them women.⁴

The advisory's estimate is 20–25% of weight lost for men vs 10–15% for women. That is a model, not a trial result.⁶ The same advisory lists low testosterone among the risk factors for losing muscle.⁶ The full story is in Do GLP-1 medicines cause muscle loss and loose skin? It covers body scans, protein, strength training and loose skin. Exercise gets its own post: Exercise on a GLP-1.

What about alcohol on a GLP-1 medicine?

The UK's NHS advises avoiding alcohol on tirzepatide. It says alcohol can make nausea and vomiting worse.¹⁹

The US nutrition advisory says alcohol may worsen nausea and reflux on these medicines and should be kept low.⁶ The labels, the research and the pancreatitis link are in Can you drink alcohol on Mounjaro or Ozempic?

Are side effects different in men?

Mostly the same, with two reported differences. Nausea and vomiting were a little more common in women on tirzepatide, and men reported far less hair loss.^3,12,13

The SURMOUNT look-back saw "a numerically higher incidence of nausea and vomiting" in women.³ Hair loss on Wegovy 2.4 mg was 0.9% in men vs 4% in women.¹² On tirzepatide it was 0.5% in men vs 7.1% in women.¹³ Both labels link hair loss to the weight lost.^12,13 More is in Does Ozempic or Mounjaro cause hair loss?

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