Sleep Doctor independently selects the products we test. We may earn a commission if you buy through the links on our site.

CPAP Dry Mouth: How to Stop It

Written by Afy Okoye

Reviewed by Dr. Michael Breus

Our Editorial Process
Updated Regularly

Continuous positive airway pressure (CPAP) machines are a common treatment for sleep apnea. While CPAP therapy is often effective in reducing nighttime breathing issues, some people experience dry mouth or other uncomfortable side effects. Preventing dry mouth can help CPAP users feel more comfortable and use their machine as prescribed.

Why CPAP Machines Cause Dry Mouth

CPAP machines use pressurized air pumped through a hose and a mask to keep a person’s airway open during sleep. Depending on the type of CPAP mask a person is using, pressurized air moves through the nose or mouth and nose. As the air travels through these passages, it can dry out tissues. 

Several factors can contribute to the development of CPAP dry mouth.

  • Reduced saliva: A CPAP machine changes the level of pressure in the mouth during sleep. This change in pressure can affect the salivary glands, which produce the saliva that keeps the mouth moist. A decrease in the flow of saliva can contribute to CPAP dry mouth.
  • Humidity: CPAP-related dryness is often worse when a sleeper is exposed to cold weather or lives in an environment with low humidity. Using a heater or turning up the thermostat can also lower the amount of indoor humidity and worsen CPAP dry mouth.
  • Mouth breathing: While most people breathe through their nose during sleep, people with obstructive sleep apnea often breathe through their mouth as well. When using a CPAP device and a nasal mask, mouth breathing can increase dryness as air escapes through the mouth.

Talking to a doctor is an important step in understanding the cause of dry mouth. While CPAP therapy can cause dry mouth, it’s important to note that other conditions such as dehydration and diabetes, as

How to Treat Dry Mouth From CPAP Therapy

Experiencing dry mouth from using a CPAP machine can be uncomfortable, but there are strategies to help mitigate this issue. Working with a doctor to find relief is important, since untreated dry mouth can lead to bad breath, tooth decay and gum disease, and other unpleasant CPAP side effects.

Use a Heated CPAP Humidifier

Heated humidifiers add moisture to the pressurized air delivered by CPAP machines. Increased humidity can make it easier to breathe at night and can reduce the risk of dryness in the nose and mouth.

Many CPAP machines come with an integrated heated humidifier, but stand-alone units are also available. Experts recommend filling the humidifier’s water chamber to its maximum level before bed to get the most humidification.

Clear Your Sinuses

Nasal congestion increases the risk of mouth breathing, which can lead to dry mouth in people who use a nasal mask. Other approaches include topical medications or sprays and rinses that use salt water to clear the nasal passages. If nasal congestion is an ongoing issue, speak with your doctor. 

Try a CPAP Chin Strap

For people who use a nasal mask and breathe through their mouth during CPAP therapy, doctors may recommend adding a chin strap to keep the mouth closed and reduce air leaks. CPAP chin straps are available in a wide variety of designs and are often placed under the mask and headgear.

Consider a New CPAP Mask Type

If a chin strap doesn’t help reduce dry mouth for nasal CPAP mask users, doctors may recommend switching to a full-face mask. Since this style of mask covers both the nose and mouth, it can prevent air leaks that can worsen dry mouth.

About The Author

Afy Okoye

Staff Writer, Sleep Health

Afy is a writer and creative strategist in San Francisco with a master’s degree in international health policy from the London School of Economics. She has written for VeryWell Health,, and Paste magazine and edited peer-reviewed journal manuscripts for Elsevier. Afy says her work with The Sleep Doctor is anything but “sleepy.” She enjoys the opportunity to learn new information and share knowledge that gives people the power to make better choices. Afy also likes to read non-fiction, do creative writing, and travel solo.

  • Position: Side sleeper
  • Temperature: Hot Sleeper
  • Chronotype: Bear