Does mouth breathing cause snoring?

Yes, mouth breathing can cause snoring, and it's one of the more common reasons people snore. When your mouth falls open in sleep, your jaw drops, your airway gets narrower and floppier, and the soft tissue in your throat is more likely to vibrate. But it isn't the only cause, and for some people the snore comes from the nose instead. Knowing which applies to you is what makes the fix work.

How does an open mouth lead to snoring?

An open mouth changes the shape of your airway. The NHS explains that snoring happens when the tongue, mouth, throat or nasal airways vibrate as you breathe, because these parts relax and narrow when you're asleep. Among the causes it lists, a mouth falling open during sleep sits right next to a blocked nose and a tongue partly blocking the throat.

Two things happen when your mouth drops open. The lower jaw swings down, which takes room away from the airway behind the tongue. And the way air enters changes. The British Snoring and Sleep Apnoea Association (BSSAA), a UK snoring organization, describes it like this: air drawn in through the nose flows gently over the curve of the soft palate into the throat, while air drawn in through the mouth hits the back of the throat head on and can set the soft tissue vibrating.

You may also notice the knock-on effects of mouth breathing in the morning, such as a dry mouth or throat. Our guide to signs you mouth breathe at night lists the common clues.

What do studies show about mouth breathing and snoring?

The research is small but points in a consistent direction. Several sleep lab studies show that breathing through an open mouth makes the airway work less well during sleep, and two small studies found that keeping the mouth closed reduced snoring in mouth breathers.

The airway gets floppier

In the 1996 study, researchers measured how easily the upper airway collapsed in six healthy volunteers as they slept, once with their mouths closed and once with them open. Opening the mouth made the airway significantly more collapsible and increased total breathing resistance. In measurements taken while the volunteers were awake, the researchers noted the gap between the teeth widened and the distance between the jaw and the hyoid bone, a small bone in the neck that anchors the tongue, got shorter. They concluded that mouth opening may contribute to breathing problems in sleep.

Breathing through the mouth is harder work in sleep

The 2003 study tested 12 healthy adults with normal noses. Awake, resistance was about the same whichever way they breathed. Asleep on their backs, it was much higher through the mouth, a median of 12.4 compared with 5.2 units through the nose. Obstructive breathing events were also far more frequent when they breathed orally. The authors suggested this mechanical advantage may explain why healthy people breathe almost entirely through the nose when they sleep.

Not everyone does, though. A 1986 study of 14 healthy adults found men took a larger share of their breaths through the mouth during sleep than women, about 29% compared with 5%, and that the share rose with age in men.

Closing the mouth reduced snoring

Two small studies tested what happens when mouth breathers keep their mouths shut. In the 2015 study, 30 people with mild sleep apnea who habitually breathed through an open mouth slept with a porous patch over the lips. Their median snoring index fell from 146.7 to 40.0 events an hour, snoring intensity dropped from about 49 to 41 decibels, and the space behind the soft palate and tongue was measurably wider.

In the 2022 study in Healthcare, 20 mouth breathers with mild sleep apnea had a baseline home sleep test, then a second test a week later on a night with their mouths taped. Thirteen of them cut their snoring index by at least half, and the median snoring index fell by 47%.

These are encouraging results, but they come from small groups, mostly people who already had mild sleep apnea, without a comparison group. Cleveland Clinic points out that there are very few mouth taping studies and they involve small populations. So the honest summary is that the mechanism is well supported and the early results are promising, but bigger trials are still needed.

What else can cause snoring?

Plenty, which is why an open mouth isn't the whole story for everyone. Cleveland Clinic lists getting older, enlarged tonsils or adenoids, a large tongue, a deviated septum, congestion from allergies or colds, alcohol and sedatives, family history, sleeping on your back and carrying extra weight. It also notes snoring is more common in men.

Some snoring happens with the mouth firmly shut. The 2014 case series found 17 of 25 people with swollen nasal turbinates, the ridges inside the nose that warm and humidify air, snored while breathing through the nose and snored less when they breathed through the mouth. For them, the nose was the problem. Our guide on why you might snore with your mouth closed covers the nose, tongue and soft palate in more detail, and how snoring happens explains the anatomy.

Often, several causes stack up. The BSSAA gives a common example: you snore because your mouth falls open, but your mouth falls open because an allergy has blocked your nose. Fixing only one of those may not be enough.

How can you tell if your snoring comes from your mouth?

A simple self-test from the BSSAA is a good start. Open your mouth and make a snoring noise. Then close your mouth and try to make the same noise. If you can only snore with your mouth open, the association says you're likely a mouth-breathing snorer.

It's not a medical test, but it's useful alongside other clues: a partner who sees your mouth hanging open, a dry mouth when you wake, or snoring that sounds worse when your jaw drops. Our guide to nose snoring vs mouth snoring walks through the other self-tests and what each result points to.

Why should you start with your nose?

Your nose is usually the reason your mouth opens in the first place. If it's blocked, your body falls back on mouth breathing, and the BSSAA notes that this can lead to snoring. Clearing your nose gives you something to breathe through when your mouth is closed.

Simple steps can help, such as a saline rinse before bed or treating allergies; our guide on how to unblock your nose before bed has more. The NHS also lists nasal strips or dilators that hold the nose open as one treatment when the airways in the nose are blocked or narrow. Try our nose test to check how well you breathe through your nose.

Once your nose is clear, there are ways to help your mouth stay closed. The NHS mentions a chin strap or a device worn in the mouth. Mouth tape is another option many people use, and our guide on whether mouth tape helps snoring covers it in depth. Some people combine both, as in mouth tape and nasal strips together. Sleeping on your side and going easy on alcohol before bed help too; see sleep position and snoring.

When should you see a doctor about snoring?

See a GP or doctor if lifestyle changes aren't helping or your snoring is having a big impact on you or your partner. The NHS says to get checked if you feel sleepy in the day, your breathing stops and starts while you sleep, or you make gasping or choking noises, because these can be signs of sleep apnoea, which can be serious if not treated.

Cleveland Clinic says you should never use mouth tape if you have nasal obstruction or congestion, chronic allergies, sinus infections, enlarged tonsils, a deviated septum or heart issues. If you're pregnant, ask your midwife or doctor before trying mouth tape. We don't recommend mouth tape for children.

Our pick (paid partner): Titan Bamboo Silk Mouth Tape

If your nose is clear and your snoring seems to come from an open mouth, our pick is Titan Bamboo Silk Mouth Tape. We haven't tested or ranked mouth tapes ourselves, and Titan's tape wasn't used in any of the studies above. This is our recommendation.

Titan describes the bamboo silk strip as soft, breathable and moisture-wicking, and says its SilkSeal adhesive is made to grip through stubble and full beards without tugging hair or leaving residue. It's one oval size, 76 by 38 mm, worn horizontally across the lips. Titan suggests 20 to 30 minutes of daytime practice before the first night.

Titan says every batch is third-party tested and certified PFAS-free, and the 30-night guarantee refunds you if your sleep isn't better after 30 nights.

Read next

• Why your mouth falls open when you sleep
• Still snoring with mouth tape? What to try next
• Nasal vs mouth breathing

* This content is for informational and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure or prevent any disease or health condition. Talk to a qualified healthcare provider about your health.