Sleep apnea and weight-loss medicines: what the trials show

What sleep apnea is and what the AHI measures

In obstructive sleep apnea, the airway repeatedly narrows or closes during sleep and breathing stops or slows. Researchers count these events with the apnea-hypopnea index, or AHI: the average number of apneas (pauses in breathing) and hypopneas (shallow breaths) per hour of sleep. A lower AHI means fewer interruptions.

Excess body fat is one cause of sleep apnea, which is why weight-loss medicines have been tested for it. The trials below enrolled adults with moderate-to-severe sleep apnea and obesity or overweight.

What the trials found, side by side

The table shows the average change in AHI from the start of each trial, in events per hour. A bigger negative number means a bigger drop. These are separate trials with different people, lengths and analysis methods, so the rows are not a head-to-head comparison.

Retatrutide figures use the "hybrid-treatment" analysis the authors chose for sleep apnea results. Their intention-to-treat analysis, which counts everyone as randomized, gave similar differences from placebo. Doses shown are those tested in the trials, once a week, and are not advice. PAP is a CPAP-type breathing machine.

Weight loss in the retatrutide sleep apnea trials

Average body weight fell by 12.5% to 22.2% across the three retatrutide doses in TRIUMPH-1-OSA and by 12.1% to 18.5% in TRIUMPH-2-OSA. On placebo it fell by 4.8% and 5.6%. Weight change was a key secondary result, measured by counting everyone as randomized.

What is approved today

The U.S. label for Zepbound (tirzepatide) lists moderate to severe obstructive sleep apnea in adults with obesity, along with weight reduction. The Atlas medicine page shows the full label wording and the boxed warning.

Retatrutide is not approved for anything. Lilly has said it plans to submit it to the FDA in the first quarter of 2027. Anything sold under its name outside a clinical trial is not an FDA-approved medicine.

What these results do not show

• The AHI is a count of breathing events. The abstracts reported changes in that count, not how many people had no sleep apnea afterward or how they felt.
• Lilly paid for all of these trials, and Lilly employees are among the authors.
• The trials ran 52 or 80 weeks. They do not say what happens to sleep apnea after treatment stops, or over many years.
• The retatrutide abstract does not give percentages for side effects. It says the most common ones were stomach and gut problems, the same pattern seen in its weight-loss trials.
• No trial here compared retatrutide with tirzepatide for sleep apnea, so the table does not rank them.

Frequently asked questions

Can weight-loss medicines treat sleep apnea?

In trials, yes. Tirzepatide and retatrutide both lowered the number of breathing interruptions per hour more than placebo in adults with moderate-to-severe sleep apnea and obesity. Tirzepatide is FDA-approved for this use. Retatrutide is not approved.

Is Zepbound approved for sleep apnea?

Yes. The U.S. label for Zepbound (tirzepatide) includes moderate to severe obstructive sleep apnea in adults with obesity. It is also approved for weight reduction.

Is retatrutide approved for sleep apnea?

No. Retatrutide is investigational and not approved anywhere. Lilly has said it plans to submit it to the FDA in the first quarter of 2027.

How much did retatrutide lower the AHI in the trials?

In TRIUMPH-1-OSA the average AHI fell by 22.9, 34.3 and 31.7 events per hour on the 4 mg, 9 mg and 12 mg doses, versus 9.9 on placebo. In TRIUMPH-2-OSA it fell by 19.2, 24.7 and 25.4, versus 10.3 on placebo.

How much did tirzepatide lower the AHI?

In the two SURMOUNT-OSA trials the average AHI fell by 25.3 and 29.3 events per hour over 52 weeks, versus 5.3 and 5.5 on placebo.

What is the AHI?

The apnea-hypopnea index is the average number of breathing pauses and shallow breaths per hour of sleep. It is how sleep apnea severity is usually scored in trials.

Where were the retatrutide sleep apnea results published?

In the New England Journal of Medicine, in October 2026, and presented at the 28th Congress of the European Sleep Research Society. The trials are TRIUMPH-1-OSA and TRIUMPH-2-OSA.

Can I get retatrutide for sleep apnea?

Not as an approved medicine. It is available only inside clinical trials or a sponsor-run expanded-access program. Products sold online under its name are not FDA-approved. A sleep or weight-management clinician can explain approved options.

Questions to ask a clinician

• Have I had a sleep study, and what was my AHI?
• Would an approved medicine, a PAP machine, or both fit my situation?
• If I use a PAP machine now, should I keep using it while I lose weight?
• How will we check whether my sleep apnea has improved?

What is still unknown

• How many people in the retatrutide trials no longer had sleep apnea at 80 weeks. The abstract does not say.
• Whether the effect lasts after treatment stops.
• How retatrutide compares with tirzepatide for sleep apnea, because no head-to-head trial in sleep apnea has been published.
• Whether regulators will include sleep apnea in any retatrutide application.

Related pages

• Tirzepatide
• Retatrutide
• News