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Retatrutide and Sleep Apnea (Obstructive Sleep Apnea)

Part of Retatrutide by Condition.

Retatrutide and Sleep Apnea (Obstructive Sleep Apnea)

Retatrutide has reported Phase 3 sleep-apnea results, but it is not an approved OSA treatment. At ADA 2026, Lilly reported that the TRIUMPH-1 nested obstructive sleep-apnea trial met its primary endpoint at 80 weeks. The largest reported mean AHI reduction was 36.1 breathing events per hour (60.6%), using the efficacy estimand, from an average baseline of 58.6 events per hour. Source: Lilly, June 6, 2026.

AHI is the apnea-hypopnea index: the number of breathing interruptions per hour of sleep. An improvement in AHI does not, by itself, establish that every participant's OSA resolved or that someone can stop CPAP. The trial results describe a group; treatment decisions require an individual's sleep assessment.

The TRIUMPH-1 OSA Sub-Study

Trial design

The pivotal TRIUMPH-1 Phase 3 trial is structured as a basket trial with nested protocols for multiple conditions, including obstructive sleep apnea. A trial design paper was published in Diabetes, Obesity and Metabolism in October 2025.
DetailValue
Parent trialTRIUMPH-1
Total participants2,339 randomized in TRIUMPH-1 overall; not all in the OSA subset
Duration80 weeks
OSA sub-studyNested protocol within TRIUMPH-1
OSA primary endpointChange in AHI events per hour at Week 80
StatusResults presented at ADA in June 2026

The nested design studied participants with both obesity and moderate-to-severe OSA within TRIUMPH-1. The overall obesity enrollment is not the OSA sample size.

What we expect to learn

The June release reported the AHI result, but did not provide a complete dose-by-dose OSA table with placebo values. The registry also specifies remission/severity thresholds, hypoxic burden, and patient-reported sleep outcomes. Those details matter when assessing who benefited and by how much.

The registered composite of AHI below 5 or mild OSA with limited daytime sleepiness should not be relabeled as universal OSA resolution. Nor is it a count of participants who stopped CPAP. Registered endpoints.

Why Weight Loss Improves Sleep Apnea

Excess weight can contribute to upper-airway obstruction, and reducing weight can improve OSA. However, the improvement is not a fixed percentage for every percentage of weight lost. The FDA's Zepbound approval summary attributes its OSA benefit largely to weight reduction, while also describing separate trials in people using and not using positive airway pressure.

Retatrutide's OSA effect should be assessed from the TRIUMPH-1 sleep-apnea results, rather than projected from weight loss in the knee osteoarthritis trial.

Precedent: Tirzepatide's SURMOUNT-OSA Trial

The most direct precedent for a GLP-1 class drug treating OSA comes from tirzepatide's SURMOUNT-OSA trial, results of which were published in 2024.

SURMOUNT-OSA key results

The SURMOUNT-OSA publication reported two 52-week trials in adults with obesity and moderate-to-severe OSA. One enrolled people not using positive airway pressure; the other enrolled people using it.
The FDA approved Zepbound (tirzepatide) for moderate-to-severe OSA in adults with obesity in December 2024, alongside a reduced-calorie diet and increased physical activity. The FDA summary describes greater AHI reductions and more participants reaching remission or mild OSA without symptoms than with placebo.

That combined endpoint is broader than “no longer having OSA,” so it should not be presented as a cure rate.

What this means for retatrutide

SURMOUNT-OSA establishes that an obesity medicine can earn an OSA indication when its own evidence supports it. It does not prove that retatrutide will be better than tirzepatide for OSA.

Lilly's July 2026 update described a planned Q1 2027 submission supported by data for obesity, knee osteoarthritis pain, and OSA. Approval and its eventual label remain regulatory decisions.

Understanding Sleep Apnea Severity

The Apnea-Hypopnea Index (AHI)

AHI measures the number of apneas (complete breathing cessations) and hypopneas (partial breathing reductions) per hour of sleep. It is the standard metric for diagnosing and grading OSA.

AHI RangeSeverityClinical Significance
<5NormalNo clinically significant sleep apnea
5-14MildIncreased daytime sleepiness; may or may not require treatment
15-29ModerateSignificant daytime impairment; CPAP typically recommended
≥30SevereHigh cardiovascular risk; CPAP strongly recommended

Why AHI reduction matters

Reducing AHI translates directly to fewer breathing interruptions per night. This improves:

  • Oxygen saturation — fewer episodes of low blood oxygen during sleep
  • Sleep architecture — fewer arousals means more restorative deep sleep
  • Daytime function — reduced fatigue, improved concentration, lower accident risk
  • Cardiovascular risk — untreated severe OSA is associated with increased risk of hypertension, atrial fibrillation, heart failure, and stroke

The Broader TRIUMPH OSA Strategy

OSA sub-studies are nested within both TRIUMPH-1 and TRIUMPH-2 (the T2D obesity trial). This dual-population approach means Lilly will have OSA data in:

  • Patients with obesity without diabetes (TRIUMPH-1)
  • Patients with obesity and type 2 diabetes (TRIUMPH-2)

Both populations have high OSA prevalence, and having data in both strengthens the case for a broad OSA indication.

Current Treatment Options for OSA

While waiting for retatrutide, people with OSA have several established treatment options:

CPAP therapy

Continuous positive airway pressure remains the gold standard for OSA treatment. It is highly effective but has well-documented adherence challenges — many patients find the mask uncomfortable and do not use it consistently.

Tirzepatide (Zepbound)

As of 2024, tirzepatide is the first and only drug specifically approved for moderate-to-severe OSA in adults with obesity. It is available by prescription now and represents a pharmaceutical alternative or complement to CPAP.

Weight loss (any method)

Any form of sustained weight loss — lifestyle changes, other medications, bariatric surgery — can improve OSA. The magnitude of improvement correlates with the amount of weight lost.

Oral appliances and surgery

Mandibular advancement devices and surgical interventions (such as uvulopalatopharyngoplasty) are options for some patients, particularly those who cannot tolerate CPAP or are not candidates for weight loss medications.

Frequently Asked Questions

Does retatrutide treat sleep apnea?

The TRIUMPH-1 OSA trial reported an improvement in AHI at 80 weeks. Lilly presented these findings at ADA in June 2026. Retatrutide remains investigational, and the results do not establish that an individual can stop CPAP or other OSA treatment.

Will retatrutide be approved for sleep apnea?

Eli Lilly has stated that it plans to include OSA data in its regulatory submissions for retatrutide. The TRIUMPH-1 OSA results have been reported, but a positive trial does not guarantee approval. Lilly has described a planned Q1 2027 submission; no approval date is established.

Should I wait for retatrutide instead of starting CPAP?

No. If you have been diagnosed with moderate or severe sleep apnea, you should begin treatment with the options available now. Untreated OSA increases cardiovascular risk, impairs quality of life, and increases accident risk. CPAP is highly effective when used consistently. Tirzepatide (Zepbound) is also available now for OSA in adults with obesity. Retatrutide is still investigational and has no established prescription-availability date.

How much weight loss is needed to improve sleep apnea?

Weight loss can improve OSA, but there is no reliable one-to-one conversion from pounds lost to AHI reduction for an individual. The retatrutide trial measured breathing events directly. Do not use a weight-loss milestone alone to decide whether CPAP is still needed; discuss reassessment with the clinician treating your OSA.

Does retatrutide affect sleep or cause insomnia?

The available trial summaries do not establish how often retatrutide causes insomnia or other sleep disturbances. Gastrointestinal events are among the most commonly reported adverse events, but their prominence does not prove that sleep-related effects cannot occur. TRIUMPH-1's OSA findings concern breathing interruptions during sleep, which is a different question from medication-related insomnia. Persistent sleep problems warrant discussion with a clinician. Lilly's ADA efficacy and safety summary.

Sources

  • Lilly ADA results, June 6, 2026
  • FDA Zepbound OSA approval
  • TRIUMPH-1 registered outcomes
  • TRIUMPH trial design paper. Diabetes, Obesity and Metabolism. October 2025. DOI: 10.1111/dom.70209
  • Eli Lilly and Company. (2025). Lilly's retatrutide achieved significant weight loss and pain relief in adults with obesity and knee osteoarthritis. Press release.
  • Malhotra, A., et al. (2024). Tirzepatide for the Treatment of Obstructive Sleep Apnea and Obesity (SURMOUNT-OSA). New England Journal of Medicine.
  • Retatrutide for MASLD — Phase 2a trial (liver-fat substudy and reported safety findings). PMC11271400
  • GLP-1 / GIP receptor agonists in obstructive sleep apnea and obesity — review (AHI improvement tracks weight loss; incretin CNS activity at the carotid body, hypothalamus and on orexin). PMC12289732
  • ClinicalTrials.gov: Retatrutide trials

Questions to ask your doctor

  • Is a GLP-1 medication an appropriate option for my condition specifically?
  • What does the evidence actually show for my condition, versus weight loss alone?
  • What are the alternatives, and how do they compare for me?
  • What risks or monitoring apply given my health history?
  • What results would be realistic, and over what timeframe?

How we keep this honest
What this is
Educational information, not medical advice. It reports published research — it doesn’t recommend that you use, obtain, or supply anything.
Regulatory status
Retatrutide and similar peptides are investigational — not approved by the FDA or any regulator. Semaglutide and tirzepatide are prescription-only medicines, available only through a licensed prescriber.
Our standard
Every claim traces to a primary source. We label the strength of evidence and flag estimates as estimates — never as clinical fact.
No commercial ties
We don’t sell, supply, or link to suppliers of any medicine, and aren’t affiliated with any manufacturer.

Do not make decisions about your health without consulting a qualified healthcare provider. For trial enrolment, see ClinicalTrials.gov. More on how we review.

Grounded in primary sources
NEJMThe LancetJAMAFDAClinicalTrials.gov

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