What obstructive sleep apnea is
MedlinePlus describes sleep apnea as a common disorder in which breathing stops or becomes very shallow during sleep, with pauses that can last from seconds to minutes. In the obstructive type, the airway collapses or is blocked during sleep. Being overweight is one of the listed risk factors, and treatments include lifestyle changes, mouthpieces, surgery and breathing devices [6].
Typical night-time signs, according to the US National Heart, Lung, and Blood Institute (NHLBI), are breathing that starts and stops, frequent loud snoring and gasping for air; during the day people may notice sleepiness, a dry mouth or headaches. Many only learn about the night-time signs from someone else [7]. MedlinePlus adds that daytime drowsiness raises the risk of car crashes and work accidents [6].
Sleep studies count these pauses. The apnea-hypopnea index (AHI) counts these events, stopped or very shallow breathing, per hour of sleep. The Zepbound® studies defined moderate OSA as an AHI of 15 to 30 events per hour and severe OSA as 30 or more [1].
What the indication covers
Section 1 of the Zepbound® label lists two uses: weight reduction and its long-term maintenance, and the treatment of moderate to severe OSA in adults with obesity. Both are alongside a reduced-calorie diet and more physical activity [1]. MedlinePlus’s plain-language tirzepatide page lists the same sleep apnea use [9].
Mounjaro®, which contains the same active ingredient, is approved for blood sugar control in type 2 diabetes in adults and in children aged 10 and older, and for lowering cardiovascular risk in adults with type 2 diabetes at high risk; it does not list sleep apnea [2]. The Zepbound® label also says it should not be used together with other tirzepatide products or with any GLP-1 receptor agonist [1].
How the US, EU and Canadian documents compare
There is no separate Zepbound® product information in the EU; tirzepatide is authorised there under the Mounjaro® name. The table summarises what each document said when we checked on 20 October 2026.
| Document | Sleep apnea wording | Where |
|---|---|---|
| Zepbound®, US prescribing information, revised 08/2026 [1] | Treat moderate to severe OSA in adults with obesity | Section 1; studies in 14.2 |
| Mounjaro®, US prescribing information, revised 08/2026 [2] | No sleep apnea indication | Section 1 |
| Mounjaro® (tirzepatide), EU product information [4] | No separate OSA indication; OSA is one example of a weight-related condition in the weight-management indication, and the OSA studies are described in 5.1 | Sections 4.1 and 5.1; package leaflet |
| Zepbound®, Canadian product monograph, authorized 11 June 2026 [5] | Treat moderate to severe OSA in adults with obesity (BMI 30 or more); not a replacement for PAP in people who need it | Sections 1 and 4.1 |
| Mounjaro®, Canadian product monograph, authorized 23 June 2026 [10] | No sleep apnea indication; type 2 diabetes in adults and children aged 10 to under 18 | Section 1 |
Dose steps for OSA
The label uses the same starting step for every indication: 2.5 mg once weekly for 4 weeks, then steps of 2.5 mg, each one coming no sooner than 4 weeks after the last. For OSA, the maintenance dosage it lists is 10 mg or 15 mg once weekly, and 15 mg is the maximum [1].
In the studies, the dose was raised over up to 20 weeks to the highest dose each person tolerated, 10 mg or 15 mg [1]. Your own dose and its timing are set by your prescriber.
How the two studies were set up
Studies 5 and 6 were two randomised, double-blind, placebo-controlled trials of 52 weeks with 469 adults in total, run under one master protocol registered as SURMOUNT-OSA (NCT05412004). Everyone had obesity, a BMI of 30 or more, and moderate to severe OSA. People with type 2 diabetes were excluded, and all received diet and activity counselling [1][3].
The difference between the two was the breathing machine. Study 5 included 234 people who could not or would not use positive airway pressure (PAP) therapy. Study 6 included 235 people already using PAP, who were asked to stop it for 7 days before the main measurement [1].
At the start, average AHI was around 50 events per hour, and roughly two-thirds had severe OSA. Mean BMI was about 39, mean age 48 in Study 5 and 52 in Study 6, and about two-thirds or more were men. Most also had raised blood pressure (about 76%) and abnormal blood fats (over 80%), and more than half had pre-diabetes [1].
What changed in the results
The main measure was the change in AHI at week 52. The label’s Table 9 shows the following for the modified intention-to-treat population; all differences from placebo were statistically significant [1].
| Measure | Study 5 placebo | Study 5 Zepbound® | Study 6 placebo | Study 6 Zepbound® |
|---|---|---|---|---|
| Change in AHI, events per hour [1] | −5.3 | −25.3 | −5.5 | −29.3 |
| Change in AHI, % | −3.0% | −50.7% | −2.5% | −58.7% |
| AHI reduced by at least half | 19% | 61.2% | 23.3% | 72.4% |
| Remission or mild OSA without symptoms | 15.9% | 42.2% | 14.3% | 50.2% |
| Change in sleep apnea-specific hypoxic burden, % min/h | −25.1 | −95.2 | −41.7 | −103 |
| Change in body weight | −1.6% | −17.7% | −2.3% | −19.6% |
Reading the results
“Remission or mild OSA without symptoms” has a set meaning in the label: an AHI below 5, or an AHI of 5 to 14 with an Epworth sleepiness score of 10 or less. Hypoxic burden describes how much oxygen levels dropped during breathing events; it fell far more on Zepbound® than on placebo in both studies [1].
The label also reports greater falls in systolic blood pressure and in high-sensitivity C-reactive protein, and better scores on a sleep-related impairment questionnaire, compared with placebo. AHI fell regardless of age, sex, ethnicity, starting BMI or starting severity [1]. The published report notes that the most frequent side effects were stomach-related and mostly mild to moderate [3].
What the studies did not answer
The label is explicit on one point: the OSA studies were not designed to look at whether, or when, people who used PAP well should give it up. The 7-day pause in Study 6 was only for measurement [1]. The EU product information adds that Study 6 does not allow conclusions about any added benefit on top of PAP, and its leaflet says tirzepatide can be used with or without PAP [4].
The trials also lasted one year, enrolled only adults with obesity and without diabetes, and did not include enough people aged 65 or older to tell whether they respond differently [1]. They report group averages, and some people improved much more than others. Whether your apnea has changed is measured by a sleep study and judged by your sleep clinician, not by how you feel on a given night. NHLBI notes that a repeat sleep study may be needed, especially after a large weight gain or loss [8].
Side effects and warnings in the label
The common side effects listed for Zepbound® apply across its uses: nausea, diarrhoea, vomiting, constipation, stomach pain, indigestion, injection site reactions, fatigue, allergic reactions, burping, hair loss and reflux. In the two OSA studies, side effects at 10 mg or 15 mg were similar to those in the weight trials, and the detailed rates in the label come mainly from those weight trials [1].
The warnings are also shared, including severe stomach side effects, kidney injury from dehydration, gallbladder disease and pancreatitis. Section 5.9 adds that slowed stomach emptying may raise the risk of food entering the lungs during anaesthesia or deep sedation, so the label asks you to tell your care team before any planned procedure [1]. NHLBI makes a related point for sleep apnea itself: tell the team before surgery, because anaesthesia and pain medicines can make it harder to keep the airway open [8].
Zepbound® and Mounjaro® are registered trademarks of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Eli Lilly.
When to get help
| Sign | Who to contact | How fast | Source |
|---|---|---|---|
| Strong belly pain that keeps going, sometimes reaching the back, whether or not you feel sick or vomit | Stop Zepbound® and contact your prescriber promptly, as the label advises | Emergency | US label, section 17 [1] |
| Feeling drowsy or struggling to stay alert while driving | Do not drive while sleepy; tell your sleep clinician | Today | NHLBI [8]; MedlinePlus [6] |
| Nausea, vomiting or diarrhoea that keeps going | Your prescriber | Today | US label, section 17 [1] |
| A planned operation, endoscopy or other procedure with sedation | Your surgical team and prescriber, before the procedure | At your next appointment | US label, section 5.9 [1]; NHLBI [8] |
| A large change in weight, or wanting to change how you use your PAP machine | Your sleep clinician | At your next appointment | US label, section 14.2 [1]; NHLBI [8] |
