In short.
Obstructive sleep apnea (OSA) is a common condition in which the upper airway repeatedly collapses during sleep. More than 900 million people have it worldwide — and in roughly 40% of them it is moderate to severe. Excess weight is the largest treatable cause.
The standard treatment is a CPAP mask: a device that blows air into the airways at night to keep them open. It works — but many people cannot or will not sleep with one. Until now, no medication had been approved for treating sleep apnea itself.
In these two trials, 469 adults with moderate-to-severe sleep apnea and obesity received a weekly injection of either Tirzepatide or placebo. After one year, Tirzepatide reduced the number of breathing pauses per hour by roughly half on average — far more than placebo, and with additional improvements in blood pressure, sleep quality and inflammation markers.
What is sleep apnea, exactly?
In obstructive sleep apnea, the throat collapses repeatedly during sleep — sometimes dozens of times per hour. This causes brief breathing pauses (apneas) or shallow breathing (hypopneas) in which oxygen levels drop. People wake up briefly each time — often without noticing.
The impact is significant: feeling exhausted during the day despite "enough hours of sleep", concentration problems, headaches, and a higher risk of cardiovascular disease, high blood pressure and traffic accidents from drowsiness behind the wheel.
It is measured with the apnea-hypopnea index (AHI) — the average number of breathing pauses + shallow breaths per hour. Above 15 is considered moderate, above 30 severe sleep apnea.
Participants in this study had on average 49 to 51 breathing pauses per hour — close to one breathing pause per minute during sleep. That is severe.
What did they study?
The question was: can Tirzepatide — an injection used for excess weight — also improve sleep apnea itself?
The researchers deliberately ran two parallel trials in order to look separately at the two patient groups that exist in real-world practice:
- Trial 1 — 234 participants who could not or would not use a CPAP mask.
- Trial 2 — 235 participants who were already using CPAP and continued to do so throughout the study.
Everyone had a BMI of 30 or higher and an AHI of 15 or more. People with diabetes (type 1 or 2) were excluded, so that the effect of the condition wouldn't be mixed up with the blood-sugar effect of Tirzepatide. All participants also received lifestyle advice (a 500 kcal/day reduction and 150 minutes of exercise per week).
Tirzepatide was titrated up over 20 weeks — starting at 2.5 mg and going up to 10 or 15 mg per week, depending on tolerability. Comparisons were made against placebo (a weekly "empty" injection), with the same lifestyle advice.
What did they find?
The results were strikingly consistent across both trials. After 52 weeks there was a substantial difference in the number of breathing pauses per hour between the Tirzepatide and placebo groups:
−25 / −29
Tirzepatide · Trial 1 / 2
A reduction of 25 to 29 breathing pauses per hour relative to placebo (~5 fewer per hour).
~50%
AHI roughly halved
Achieved by 61% (without CPAP) to 72% (with CPAP) of Tirzepatide participants, versus 19–23% on placebo.
−18% / −20%
Weight loss over 52 weeks
Tirzepatide group, versus 1.6% / 2.3% with placebo.
42 / 50%
Reached PAP-free threshold
Share of participants whose AHI dropped below the level at which CPAP therapy is, per guidelines, often no longer required.
Beyond these headline numbers, there were also clear improvements in:
- Hypoxic burden — the cumulative drop in oxygen during the night — fell substantially. This figure correlates more strongly with cardiovascular risk than the AHI alone.
- Blood pressure — roughly 7 to 10 mmHg lower (systolic).
- Sleep quality — patients reported fewer sleep problems and less daytime sleepiness.
- Inflammation marker hsCRP — roughly halved. This is a general marker of systemic inflammation in the blood.
What about side effects?
The side-effect profile was familiar to anyone tracking Tirzepatide: mainly gastrointestinal complaints in the first weeks of dose escalation — diarrhoea (~22–26% vs 9–13%), nausea (~22–25% vs 5–10%), constipation (~15–16%) and vomiting (~9–17%). Mostly mild to moderate, and largely transient.
What stood out as not being a difference-maker: serious adverse events occurred at similar rates in both groups (in trial 2, even less often on Tirzepatide), and there were no deaths. Two confirmed cases of acute pancreatitis were reported in the Tirzepatide group of trial 2 — a known, rare side effect. There were no cases of thyroid cancer.
What does this mean for you?
Do you have moderate-to-severe sleep apnea, and either wear a CPAP mask at night — or did you find one impossible to keep using? Then this is genuine news.
For the first time, there is a medication that demonstrably and substantially lowers the number of breathing pauses per hour. It does not replace CPAP under current guidelines, but it can be an important addition — particularly for people who can't tolerate CPAP.
Three practical points:
- Diagnosis belongs with a sleep specialist. Suspect you might have sleep apnea? Snoring, daytime fatigue, morning headaches — your GP can refer you to a sleep clinic. A sleep study (polysomnography) confirms or rules out the diagnosis.
- Lunaris does not replace a sleep clinic or pulmonologist. We prescribe Tirzepatide for overweight/obesity. If you also have sleep apnea, that may be an important additional reason to consider treatment — but the CPAP side stays with your treating specialist.
- Good coordination. If you already use CPAP or have had a sleep study, we'll ask about it during intake. When in doubt, we coordinate with your treating sleep specialist before treatment begins.
Important: in Europe, Tirzepatide is currently approved for obesity and type 2 diabetes — not specifically for sleep apnea. The effect on sleep apnea is a "side benefit" supported by this trial, but not a registered indication. The registered indication may change in future based on evidence like this.
Important caveats.
— Only people with obesity
The trials only included people with a BMI of 30 or higher. We therefore don't know whether Tirzepatide would have the same effect in slimmer people with sleep apnea. For Lunaris's target group (adults with overweight/obesity) the results are representative.
— 52 weeks is not a lifetime
Sleep apnea is a chronic condition; these trials lasted one year. Whether the effect on AHI is sustained over years cannot be inferred from this study. Longer-duration studies are running, and the SURMOUNT-MMO trial is also examining cardiovascular outcomes.
— No people with diabetes
People with type 1 or type 2 diabetes were deliberately excluded. That has to do with Tirzepatide also lowering blood sugar — those mixed effects would muddy the sleep-apnea findings. Other research is running for people who have both diabetes and sleep apnea.
— Sponsored by the manufacturer
The study was funded by Eli Lilly, the maker of Tirzepatide. That's standard for phase-3 research and doesn't necessarily compromise scientific quality — the NEJM editorial team and peer review ensure that. But it's relevant to know.
— CPAP remains first-line
The American Academy of Sleep Medicine guidelines (and their Dutch equivalents) still prioritise CPAP therapy for people with OSA symptoms. Tirzepatide is not a replacement — it's a proven additional or alternative route, especially for people who cannot tolerate CPAP.
— Original source
Malhotra A, Grunstein RR, Fietze I, et al. Tirzepatide for the Treatment of Obstructive Sleep Apnea and Obesity. The New England Journal of Medicine, 21 June 2024.
DOI: 10.1056/NEJMoa2404881 · ClinicalTrials.gov: NCT05412004 · Full publication subscriber-only; abstract openly available.
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