The FDA approved Zepbound (tirzepatide) in December 2024 for the treatment of moderate-to-severe obstructive sleep apnea (OSA) in patients with obesity after research showed that the medication improved outcomes in these patients.

Sleep apnea is among the most common sleep disorders. It occurs when the airways relax and block breathing during sleep. Patients may repeatedly stop breathing, leading to disrupted sleep, snoring, and excessive sleepiness during the day.

Now new research has shown that certain patients seem to benefit more than others from the medication. Patients with the most severe sleep apnea along with those who are younger and have less severe obesity experienced nearly twice the reduction in symptoms compared to those who are older and have more severe obesity.

“Currently, clinicians can only point to the average treatment responses, showing that, on average, patients can expect around a halving of their sleep apnea severity beyond what is seen with a placebo,” study author Scott Sands, PhD, an associate professor of medicine at Brigham and Women ’s Hospital and Harvard Medical School in Boston, said in a statement. He added that this provides physicians a better idea of which patients will benefit the most and the least from the medication.

The Link Between Obesity and OSA

One third of patients with obesity have sleep apnea, and the most common causes are anatomic. When people gain weight, they collect adipose tissue in different parts of the body, including their necks, which then puts weight on their airways, especially when they are sleeping.

Fat mass on the neck and around the throat also causes the airways to collapse, leading to sleep apnea. A study published in the journal Sleep found that many people with obesity also had an enlarged tongue due to fat cells that collect there, which can also constrict the airway.

According to the study authors, “excess fat is often deposited in the tongue in obese patients with sleep apnea.” Abdominal fat can also have an influence on lung volume, affecting breathing in general at the upper airway.

Additionally, there’s a link between obesity and inflammation, which can lead to disfunction in the central nervous system. All of this impairs the ability of the body to maintain a normal respiratory rate. “This might also cause patients to go into periods of apnea,” said Ziyad Al-Aly , MD, a clinical epidemiologist at the Washington University in St. Louis and a national expert on GLP-1 research.

Why GLP-1s Improve OSA Outcomes

Researchers have long known that weight loss can improve sleep apnea symptoms. A study published in The New England Journal of Medicine found that patients who did and didn’t use a continuous positive airway pressure (CPAP) machine both experienced improvements after taking tirzepatide.

By measuring the apnea-hypopnea index — the number of times that a patient slowed or stopped breathing during sleep due to OSA — researchers found that all patients taking the medication showed improvements in symptoms. The study looked at secondary outcomes as well, including systolic blood pressure, cardiovascular risk factors, and oxygen levels, as well as patient-reported outcomes, all of which improved in patients taking the medication.

It’s not known whether it’s completely related to a reduction of adipose tissue at the neck and tongue or if there is another side effect from the medications that causes a reduction in sleep apnea. The data that we have so far don’t show us, said Carolynn Francavilla, MD, a nationally recognized obesity physician who owns and operates Green Mountain Partners for Health and Colorado Weight Care, both in Denver.

“It’s possible that tirzepatide is doing something unique structurally to where the fat loss occurs, for example, in the tongue, but right now all we know is that when people lose weight, they have improved sleep apnea and that these medications lead to weight loss,” said Francavilla.

Patients Who Experience the Most Improvement

At a recent presentation given at the 2026 American Thoracic Society (ATS) International Conference, which took place this month in Orlando, Florida, researchers discussed which patients saw the most improvements.

“The patients with the worst collapsibility in their airways were the ones who seemed to benefit the most,” said Atul Malhotra, MD, a professor of pulmonary critical care and sleep medicine at UC San Diego Health and the lead author of the NEJM study.

Additionally, those with less severe obesity and younger patients all did better on the medication. Though it’s also worth noting that most people taking the medication saw some improvement.

“This makes sense with what we see clinically, that those at a lower weight are going to be able to see that improvement more quickly than those who have more weight to lose,” said Francavilla. She added that it’s also clear that patients tend to snore less, a symptom associated with sleep apnea, once they get to a certain weight threshold. While snoring does not always indicate OSA, it’s one of the most obvious signs of it.

It’s worth noting that while researchers don’t have the same data for semaglutide to show its impact on OSA, it’s likely that both medications lead to weight loss, which in turn leads to a reduction in OSA. But the only data right now are on tirzepatide, which is why it’s the only GLP-1 medication approved by the FDA for use in patients with OSA.

Francavilla contends that just because patients who are younger and have less severe obesity respond better to the treatment, that doesn’t mean these are the only patients who will benefit. She also contends that many patients might not realize that they have obesity considering that obesity can be a BMI of just 27.5 in some individuals including Asian patients. This means that many people might not realize that they are within the patient populations that can benefit from taking these medications.

She added that patients using a CPAP machine might benefit from adding the medication because it may allow them to use the machine at a lower, more comfortable setting. For some patients, the medication might mean that patients can see a benefit before they have to start CPAP therapy or they may be able to get off CPAP therapy altogether. It really just depends on the patient.

“Not all patients will find that tirzepatide is a singular solution to their OSA; for many of them, it will be an adjunct to the CPAP therapy they’re already using,” said Francavilla.

Al-Aly reported having served as a consultant for Pfizer. Francavilla reported having financial relationships with Eli Lilly and Novo Nordisk.Malhotra reported receiving consulting and/or research funds from Respironics, Pfizer, Itamar Medical, Restore Medical, Inspiration Medical, Apnex, NMT Medical, and Cephalon.