GLP-1 Side Effects in Women vs Men: What the Trials Measured

Women and men get the same list of side effects on Ozempic, Wegovy, Mounjaro and Zepbound, but not at the same rate. Two differences are measured. Women report nausea and vomiting more often, and they lose a larger share of their body weight: 10.9% against 6.8% across six trials analyzed by sex.^[1] Women also report more hair loss on both the Wegovy and Zepbound labels, and more hip and pelvis fractures on Wegovy in its heart-outcomes trial.^[10][11] Part of the nausea gap tracks body size, since a fixed dose is more drug per kilogram in a lighter person. Part of it does not: in one semaglutide analysis, women reported more nausea than men at the same blood level of the drug.^[2] The heart and symptom benefits measured so far did not differ by sex.

What differs by sex, drug by drug

Nausea and vomiting: more common in women

Stomach side effects are the main ones for everyone. In the first three Wegovy weight-loss trials, 43.9% of people on semaglutide 2.4 mg reported nausea against 16.1% on placebo, and 4.3% stopped the drug because of a gastrointestinal problem.^[18] None of the four US labels splits those numbers by sex. The sex split has to be read from the trial analyses, and it points the same way each time.

• Semaglutide (Ozempic). A Novo Nordisk analysis pooled 1,552 adults from four diabetes trials and matched each person’s side effects to the level of drug in their blood. Women reported nausea more often than men across the full range of drug levels, and vomiting showed the same pattern.^[2]
• Tirzepatide (Mounjaro, Zepbound). In a Lilly analysis of the SURMOUNT trials, women made up 76% of SURMOUNT-1 participants who reported a stomach side effect and 63% of those who did not. The other three trials ran the same direction.^[6] The paper did not test sex formally, so treat this as a consistent pattern in its baseline table rather than a measured risk ratio.
• Dulaglutide and liraglutide. In two Japanese phase 3 trials analyzed by sex, women had more adverse events, including nausea, in every treatment group.^[4] In a Chinese clinic cohort on liraglutide, men had about one-fifth the odds of stomach side effects (adjusted odds ratio 0.19).^[5]
• Stopping the drug. In Scotland’s national diabetes records, female sex was one of three traits tied to stopping a GLP-1 for what looked like intolerance, alongside lower BMI and more advanced kidney disease.^[7] That study is covered in not taking it vs not tolerating it.

Most people who get nausea on these drugs get it during or shortly after the dose increases, and for most it is mild to moderate and passes.^[18] That timing is the same for both sexes; how long GLP-1 side effects last covers it.

Why women report more: body size explains part of it

Every adult gets the same fixed dose. A 2.4 mg injection is the same amount whether the person weighs 60 kg or 130 kg, and the average woman weighs less than the average man. The Ozempic label states the consequence directly: semaglutide exposure goes down as body weight goes up, though the label judges its 0.5 mg and 1 mg doses adequate from 40 to 198 kg.^[12] For liraglutide the effect has been measured. A 60 kg person had about 41% more drug in the blood than a 100 kg reference person, and women had 32% more than men of the same weight.^[3] Nausea rises with drug level, so more drug per kilogram is a plausible cause of more nausea.

The labels for Wegovy, Zepbound and Mounjaro say sex and body weight have no clinically meaningful effect on drug levels.^[10][11] That is a judgment about efficacy and dosing, not a statement that levels are identical. Mounjaro uses nearly the same wording.^[13]

Body size does not close the gap. In the semaglutide analysis, women and men on 1 mg reached almost the same average blood level, 31.7 against 29.9 nmol/L, and women still reported nausea more often at every level.^[2] So something besides dose per kilogram is involved. The candidates are hypotheses, not findings: differences in how the stomach empties, a higher background rate of functional gut disorders in women, and differences in what people choose to report. No study has separated them.

What the data do support is the reason doses are raised slowly. In the same analysis, the extra nausea that came with higher drug levels was blunted by stepping up the dose gradually.^[2] Your prescriber sets that pace. The finding applies to anyone struggling with nausea, not only women.

Weight loss: women lose a larger share

A 2026 systematic review of 64 randomized trials found one consistent subgroup difference. In the six trials that reported by sex, covering 19,906 people, women lost 10.9% of body weight and men 6.8%.^[1] The pattern repeats inside individual programs. In the semaglutide diabetes trials, the model estimated 7.0% loss for women on 1 mg against 4.5% for men.^[2] In the STEP-HFpEF heart failure trials, semaglutide 2.4 mg cut weight by 9.6% more than placebo in women and 7.2% more in men.^[8]

Percentage loss is not a pure measure of drug effect. Women start with a higher share of body fat and usually a lower starting weight, so the same kilograms lost is a bigger percentage. Who loses more weight on a GLP-1 takes that apart. The outcomes that matter beyond the scale did not differ. In STEP-HFpEF, heart failure symptom scores improved by 7.6 points more than placebo in women and 7.5 in men.^[8] In the SUMMIT trial of tirzepatide, the reduction in heart failure events or cardiovascular death was similar, with hazard ratios of 0.66 in women and 0.61 in men.^[9]

Two side effects the labels split by sex

Hair loss. This is the largest sex gap on the Wegovy and Zepbound labels. On Wegovy 2.4 mg, 4% of women and 0.9% of men reported hair loss, and at the 7.2 mg dose it was 8.4% of women and 0.2% of men.^[10] On Zepbound it was 7.1% of women and 0.5% of men.^[11] Both labels tie it to weight reduction. The mechanism and what to do about it are covered in GLP-1 hair loss and muscle loss.

Hip and pelvis fractures. In the Wegovy cardiovascular outcomes trial, more hip and pelvis fractures were reported in women on the drug than on placebo.^[10]

“more fractures of the hip and pelvis were reported on WEGOVY than on placebo in female patients: 1% (24/2,448) vs. 0.2% (5/2,424)”^[10]

— Wegovy prescribing information, section 6.1 (DailyMed)

The same label reports a similar gap in patients 75 and older. It is a small absolute number, but it is the only fracture figure on these four labels that names women. The bone evidence is reviewed in GLP-1s, bone density and fracture risk.

What the adverse-event report databases show

FDA’s adverse event reporting system (FAERS) collects reports from patients, doctors and manufacturers. Its counts are reports, not cases caused by the drug, and they cannot give a rate because nobody knows how many people took the drug or how many problems went unreported. Most people on these drugs are women, so women file most reports. With that limit stated, here is what the public FAERS data show for reports listing each drug, by sex.

For both drugs, women’s share of nausea reports is higher than their share of all reports.^[14] That fits the trial data. It is still a reporting pattern, and studies that mine these databases do not always agree. A Korean study found women reported side effects of diabetes drugs more often than men across almost every body system, with GLP-1 drugs among the classes showing the gap.^[15] A FAERS analysis of tirzepatide that ranked signals within each sex found that the strongest signals in men were gastrointestinal, while in women they were injection-site and general complaints.^[16] Disproportionality studies like these find reporting signals. They do not measure risk.

One signal leans toward men. A 2026 FAERS study of NAION, a rare condition in which the optic nerve loses its blood supply, found the reporting signal for semaglutide was stronger in men than in women, with an adjusted odds ratio of 3.33.^[17] That is a reporting signal, not a measured risk, and it needs confirmation in studies that follow patients. The full evidence is in GLP-1s, NAION and the eyes.

Side effects in women: the specific questions

Trials of these drugs enrolled mostly women; the pooled Wegovy weight-loss trials were 71% female.^[10] Several questions apply only to women and have their own pages.

• Birth control. Tirzepatide can make the contraceptive pill less reliable, and the Zepbound label gives a backup-method instruction tied to the first weeks and to each step up in dose.^[11] The semaglutide labels carry nothing comparable. Details: GLP-1s and hormonal birth control.
• Pregnancy. Semaglutide leaves the body slowly, so the Ozempic and Wegovy labels set a two-month gap between the last dose and trying to conceive.^[12][10] See GLP-1s, pregnancy and trying to conceive.
• Periods. What is and is not known about cycle changes on these drugs: see GLP-1s and your period.
• Menopause. The evidence specific to women after menopause is thin. See GLP-1s after menopause.
• Vaginal dryness, odor and infections. What the label and the case reports do and do not show: Ozempic and vaginal symptoms.
• Hair loss. More common in women on every label figure above, by a factor of four or more. See GLP-1 hair loss and muscle loss.

Side effects in men: the specific questions

Men were the minority in the obesity trials, so the men’s evidence is thinner. Three questions come up most.

• Testosterone and fertility. The trial evidence in men is small. See GLP-1s, men’s testosterone and fertility.
• Erectile function. None of the four labels mentions erectile dysfunction; the published studies are observational. See GLP-1s and erectile dysfunction.
• Penis size. No study has measured it on a GLP-1. What weight loss does to the visible length is covered in GLP-1s and penis size.
• Vision. The NAION reporting signal above is stronger in men. See GLP-1s, NAION and the eyes.

What this means if you are starting

Sex does not change which drug works or whether it works. It changes the odds of two things you will notice. A woman starting Ozempic or Mounjaro is more likely than a man to have nausea during the dose increases and more likely to notice shedding hair. A man is likely to lose a smaller percentage of his weight. Neither difference is a reason to choose one drug over another, and no label sets a different dose by sex. If side effects are hard to tolerate, the measured lever is the pace of dose increases, which your prescriber controls.