Patient guide · Reviewed May 2026
Mounjaro and Sleep Apnoea — What the Clinical Evidence Shows
Mounjaro (tirzepatide) has become the first pharmacological treatment for obstructive sleep apnoea (OSA) registered in Australia. In January 2026, the TGA expanded the indication for tirzepatide — previously approved for type 2 diabetes and weight management — to include moderate-to-severe obstructive sleep apnoea in adults with obesity.
Australian doctors described the approval as a major step forward. This guide explains what the evidence shows, who it applies to, and what this means for Australian patients on Mounjaro who also have sleep apnoea.
Published 2026-05-01 · Clinically reviewed 2026-05-31
Patient guide · Reviewed May 2026
The SURMOUNT-OSA Trial — What It Found
The TGA approval is based on the SURMOUNT-OSA phase 3 clinical trial, published in the New England Journal of Medicine in June 2024. The trial comprised two…
The TGA approval is based on the SURMOUNT-OSA phase 3 clinical trial, published in the New England Journal of Medicine in June 2024. The trial comprised two independent randomised, double-blinded, placebo-controlled studies across 58 sites in nine countries — including Australia.
Study 1 — Patients not on PAP (positive airway pressure) therapy:
Patients with moderate-to-severe OSA and obesity who were unwilling or unable to use CPAP machines. This is the most significant cohort — people managing OSA without existing treatment.
Results at 52 weeks: tirzepatide led to a mean AHI (apnoea-hypopnea index) reduction from baseline of 27.4 events per hour, compared to 4.8 events per hour for placebo. The percentage AHI reduction was up to 62.8% — approximately 30 fewer breathing disruptions per hour of sleep compared to placebo.
The mean AHI baseline was 51.5 events per hour, which fell to a mean of 25.3 AHI events per hour after treatment — a reduction of more than 50%.
Study 2 — Patients on PAP therapy:
Patients already using CPAP who continued their PAP therapy throughout the trial. Tirzepatide provided additional AHI reduction on top of CPAP. In the efficacy estimand, 51.5% of participants treated with tirzepatide at the highest dose met the criteria for disease resolution.
Secondary outcomes: Tirzepatide also reduced body weight, hypoxic burden (a measurement capturing OSA-related cardiovascular risk), high-sensitivity CRP (inflammation marker), and systolic blood pressure. Patient-reported outcomes showed significant improvements in sleep disturbance, sleep-related impairment, functioning, and health-related quality of life following tirzepatide treatment.
The safety profile was consistent with previous Mounjaro trials — predominantly mild-to-moderate gastrointestinal side effects during dose escalation.
Why Obesity and Sleep Apnoea Co-Occur
Obstructive sleep apnoea and obesity are closely linked through several mechanisms:
Fat deposition around the upper airway: Excess fat in the neck, tongue, and soft palate narrows the upper airway during sleep. Airway collapse produces the characteristic breathing disruptions of OSA.
Reduced respiratory muscle function: Obesity affects the mechanical efficiency of breathing muscles, increasing the risk of airway collapse during sleep.
Metabolic connection: Obesity, insulin resistance, and metabolic syndrome share inflammatory pathways with OSA. GLP-1 receptors are expressed in brain regions involved in respiratory control — potentially explaining benefits beyond weight loss alone.
This metabolic overlap is why GLP-1 medications are emerging as relevant treatments for OSA, not merely as an indirect effect of weight loss.
Patient guide · Reviewed May 2026
What the TGA Approval Means
The TGA's January 2026 approval specifically covers moderate-to-severe obstructive sleep apnoea in adults with obesity. This is the first time any…
The TGA's January 2026 approval specifically covers moderate-to-severe obstructive sleep apnoea in adults with obesity. This is the first time any pharmacological treatment has been approved for OSA in Australia.
Previously, management of OSA was limited to:
- CPAP (continuous positive airway pressure) — most effective but poorly tolerated by many patients
- Mandibular advancement devices (dental splints)
- Surgery in selected cases
- Lifestyle modification including weight loss
Tirzepatide (Mounjaro) is now a formally approved pharmacological addition to this toolkit — specifically for patients with both moderate-to-severe OSA and obesity.
Can You Stop CPAP if You Are on Mounjaro?
This is the most important practical question — and the answer requires specialist guidance, not a unilateral decision.
The SURMOUNT-OSA trial showed significant AHI reduction with tirzepatide, and 43–51.5% of participants met the criteria for disease resolution at 52 weeks. This means a meaningful proportion of patients on Mounjaro may improve sufficiently that CPAP is no longer needed.
However:
Do not stop CPAP without a repeat sleep study. AHI reduction must be confirmed with objective monitoring — either polysomnography (full sleep study) or home sleep testing — before CPAP settings are changed or CPAP is discontinued. Reducing CPAP based on subjective symptoms alone risks leaving OSA undertreated.
The appropriate pathway:
- Continue CPAP as prescribed while starting Mounjaro
- After significant weight loss (typically 6–12 months into therapy), discuss a repeat sleep study with your GP or sleep specialist
- If the repeat sleep study confirms AHI has reduced to mild or normal levels, your sleep specialist may recommend trialling reduced CPAP pressure or cessation with monitoring
Clinical benefits of Mounjaro in both PAP-treated and untreated patients were highly significant. But the clinical pathway for CPAP adjustment must involve specialist assessment — not self-management.
Patient guide · Reviewed May 2026
What About Ozempic and Sleep Apnoea?
The definitive phase 3 sleep apnoea data is for tirzepatide (Mounjaro). Semaglutide (Ozempic/Wegovy) produces significant weight loss — which independently…
The definitive phase 3 sleep apnoea data is for tirzepatide (Mounjaro). Semaglutide (Ozempic/Wegovy) produces significant weight loss — which independently improves OSA in most patients — but does not have the same dedicated OSA trial programme.
For patients currently on Ozempic who also have OSA, significant weight loss is expected to improve sleep apnoea. A repeat sleep study after meaningful weight loss is appropriate. However, the TGA indication for OSA treatment specifically covers tirzepatide, not semaglutide.
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Frequently asked questions
Does Mounjaro help sleep apnoea?
Yes. The SURMOUNT-OSA phase 3 trial demonstrated a mean AHI reduction of up to 62.8% with tirzepatide compared to placebo. The TGA approved Mounjaro for moderate-to-severe OSA in Australian adults with obesity in January 2026 — making it Australia's first registered pharmacological treatment for OSA.
Can I stop CPAP if I am taking Mounjaro?
Not without specialist assessment. A repeat sleep study is required to objectively confirm AHI reduction before CPAP settings are changed or discontinued. Discuss with your GP or sleep specialist after significant weight loss.
Does Ozempic help sleep apnoea?
Semaglutide produces weight loss that independently improves OSA in most patients, but does not have dedicated phase 3 OSA trial data. The TGA's OSA indication specifically covers tirzepatide (Mounjaro). Ozempic patients with OSA should discuss a repeat sleep study with their sleep specialist after significant weight loss.
What is the AHI and what does a reduction mean?
AHI (apnoea-hypopnea index) measures the number of breathing disruptions per hour of sleep. Normal is below 5 events per hour. Mild OSA is 5–15, moderate is 15–30, severe is above 30. A reduction from 51.5 to 25.3 events per hour — as seen in SURMOUNT-OSA Study 1 — represents a move from severe to moderate OSA on average, with a subset achieving disease resolution.
Does my GP need to refer me to a sleep specialist on Mounjaro?
If you have known or suspected OSA and are starting Mounjaro, discuss a referral to a sleep physician for baseline and follow-up assessment. Medicare provides rebates for sleep studies ordered by GPs or specialists.
SURMOUNT-OSA NEJM June 2024; Eli Lilly SURMOUNT-OSA press release June 2024; TGA tirzepatide OSA approval January 2026; Dermatology Republic AU report January 2026; Sleep journal patient-reported outcomes August 2025.
This article is for educational purposes only. It does not constitute medical advice. Always consult your GP or a specialist about your individual health circumstances.
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