Mouth breathing might sound harmless, but chronic mouth breathing can literally reshape your face and impair your health in surprising ways. In fact, the derogatory term “mouth breather” has some truth behind it – persistently breathing through your mouth (instead of your nose) is linked to changes in facial structure, dental alignment, and a host of health issues. From elongated “adenoid face” features to sleep troubles and fatigue, the impacts are real. The good news? By understanding why nasal breathing is nature’s default and how mouth breathing affects us (especially children), you can take steps to correct this habit and improve both your appearance and well-being[1][2].

Why Nasal Breathing Matters More Than You Think

Humans are meant to breathe through the nose. Our nasal passages aren’t just for show – they act as built-in air filters and conditioners. Air drawn in through the nose gets warmed, humidified, pressurized, and cleansed by mucus and tiny hairs before reaching our lungs[3]. This not only makes breathing more efficient, it also blocks allergens and pathogens. By contrast, mouth breathing bypasses these advantages, bringing in cool, dry, unfiltered air. The result? A dry mouth and throat (hello morning “cottonmouth” and bad breath), and less efficient oxygen uptake.

In fact, research shows we can extract ~20% more oxygen from each breath by nasal breathing instead of mouth breathing[4]. “That’s no small difference, especially when you’re exercising,” notes science journalist James Nestor, author of the bestseller Breath: The New Science of a Lost Art. In one experiment, athletes who switched to nose-only breathing during exercise significantly increased their endurance and felt their effort was easier[5]. More oxygen per breath means better stamina and recovery, as well as a calmer nervous system response. Nasal breathing also produces nitric oxide, which helps dilate blood vessels and improve circulation in the body (mouth breathing doesn’t do this).

Nestor points out that virtually all other mammals breathe through their noses by default – even a cheetah sprinting at 60+ mph keeps its mouth closed[6].

Humans, however, have become “the worst breathers in the animal kingdom” due to modern habits. -James Nestor

We often unconsciously mouth-breathe from stress, poor posture, or chronic nasal congestion. Over time, this habit can turn into a vicious cycle: breathing through the mouth can cause the nasal passages to stay constricted (“use it or lose it”), making nose breathing feel harder[7]. Meanwhile, inhaling through the mouth pulls air in with less pressure, which allows the throat tissues to sag inward and narrow the airway – making breathing even more difficult[8]. In other words, mouth breathing begets more mouth breathing (and snoring), whereas nasal breathing helps “tone” and open the airway, leading to easier nose breathing over time[8].

It’s also important to realize that the nose is our first line of immune defense. Breathing through your nose traps dust, pollutants, and germs in your nostril hairs and mucus lining, reducing what reaches your lungs[9]. One study found that people with more nasal hair had significantly lower risk of asthma from allergies[9]. Mouth breathing, on the other hand, bypasses these filters, potentially exposing you to more colds and respiratory infections. No wonder many cultures traditionally emphasized keeping the mouth shut – even 19th-century Native American tribes warned that mouth-inhaled air “sapped the body of strength, deformed the face, and caused disease,” whereas nose breathing kept the body strong and the face “beautiful”[10].

Facial Structure: How Mouth Breathing Changes Your Face

One of the most striking effects of chronic mouth breathing is how it can alter facial development, especially in children. Orthodontists and ENT specialists can often spot a “mouth breather” face on sight. Common features include a longer, narrower face, an underdeveloped jaw or chin that looks set back, an open-mouth posture with lips apart, and misaligned or crowded teeth[1][2]. This constellation of traits is sometimes called “long face syndrome” or “adenoid facies” in medical literature – and mouth breathing is a major culprit.

When a child habitually breathes through their mouth, the tongue drops from the roof of the mouth and the jaw hangs open. This posture has cascading effects on how the face grows. The tongue no longer presses against the palate (roof of the mouth) as it should, so the upper jaw doesn’t widen properly and often becomes V-shaped and narrow. The cheeks and lips, meanwhile, exert inward pressure on the dental arch. Over years of mouth breathing, these forces lead to a narrow upper jaw and dental arch, causing teeth crowding and a high chance of braces being needed later[13][14]. The lower jaw (mandible) tends to growth downward and backward instead of forward, resulting in a receding chin and a less defined jawline[15][16]. The entire face can take on a longer, thinner appearance as vertical growth is exaggerated. As one dental clinic explains, “mouth breathing leads to crooked teeth, an underdeveloped jaw and poor development of the face”[2].

Multiple studies, including a famous series by Dr. Egil Harvold in the 1970s, have demonstrated this cause-effect. Harvold’s research involved blocking the nasal airways of young monkeys, forcing them to breathe only through their mouths. The result: all the mouth-breathing monkeys developed the telltale facial changes – narrowed dental arches, crooked teeth, longer faces, and receded jaws – compared to the nasal-breathing control group[17][8]. In just months, their oral structures deformed; after two years, the damage was even worse. This experiment, though extreme, vividly shows how inadequate nasal breathing can distort normal facial growth.

Dr. John Mew, a prominent orthodontist, similarly documented that children who switched from mouth breathing to nasal breathing showed remarkable improvements in facial development. In one report, a teen boy who began mouth breathing (after developing allergies that blocked his nose) saw his formerly broad face become noticeably longer and narrower within just 3 years[18][16]. His jaw slipped back, his chin doubled, and his airway reduced – resulting in new sleep apnea issues[16]. Cases like this are sadly common. As Dr. Mew put it, many modern teens have “long, narrow and flat faces with sunken cheeks, receded chins, narrow jaws and prominent noses” because they grew up breathing through an open mouth[19].

"People, and in particular children, who overuse mouth breathing, have changes in the structure of the face that, to be quite direct, makes them far more unattractive than if they were to nasal breathe." -Dr. Andrew Huberman, Stanford neuroscientist

Even Dr. Andrew Huberman – a Stanford neuroscientist and popular health podcaster – has sounded the alarm. In a 2023 conversation with Chris Williamson, Dr. Huberman noted that excessive mouth breathing in childhood actually changes face shape, often making people less attractive. He highlighted how chronic mouth breathers can develop a recessed chin and even a droopy-eyed look due to underdeveloped facial muscles around the sinuses[20]. The differences can be striking, but Huberman also stressed that these changes are to some extent reversible if nasal breathing and proper oral posture are restored early on[21]. In other words, a child who learns to keep their mouth closed and tongue on the palate can catch up in facial growth – a fact that gives hope to concerned parents.

Importantly, it’s not just genetics at play here. Our modern environment and habits contribute. In their book Jaws: The Story of a Hidden Epidemic, orthodontist Sandra Kahn and biologist Paul Ehrlich argue that a combination of soft modern diets and prevalent mouth-breathing has led to an epidemic of underdeveloped jaws and crowded teeth in today’s youth[22][23]. They point out that skulls of pre-industrial humans almost never show crooked teeth or tiny jaws – those ancient skulls have broad palates, forward-grown jaws, and roomy airways[24][25]. In contrast, many modern skulls (and faces) exhibit the opposite: shrunken jaws set back in the face and misaligned teeth[25]. Our ancestors chewed tough foods for hours a day and naturally breathed through their noses, which promoted strong jaw development. Today’s kids eat soft processed foods and often breathe with mouths open, leading to narrower jaws and more orthodontic problems. It truly is a “hidden epidemic” of stunted facial growth. The authors of Jaws even share dramatic before-and-after photos: children who stopped mouth breathing (through therapy and exercises) developed broader smiles and more defined faces compared to those who didn’t[26][27]. The sooner the correction, the better the results.

Health Consequences of Chronic Mouth Breathing

Beyond cosmetics and jaw alignment, mouth breathing can wreak havoc on your health. If you or your child habitually sleeps or walks around mouth-agape, you may experience:

Poor sleep & snoring: Breathing through your mouth at night dries out the throat and can lead to or worsen snoring and obstructive sleep apnea. Mouth breathing narrows the airway (especially when lying down)[28], and an obstructed airway leads to noisy, labored breathing at night. People who mouth-breathe often wake up frequently (even without realizing it) due to airway restriction. The outcome is fragmented, low-quality sleep and daytime fatigue.
Daytime fatigue & brain fog: Because of the sleep disruptions and lower oxygen efficiency, chronic mouth breathers often feel tired and unfocused. In children, this can manifest as irritability and ADHD-like behavior. In fact, some kids diagnosed with attention or hyperactivity disorders are simply not sleeping well due to mouth-breathing and minor apnea at night[29]. Lack of oxygen and rest makes them restless and unfocused in school. Studies have found that treating mouth breathing or apnea in children often improves their behavior and concentration.
Altered oxygen and CO₂ balance: Mouth breathing typically leads to faster, more shallow breaths that only fill the upper lungs. This can reduce blood CO₂ levels and oxygen delivery to tissues. Nose breathing, by contrast, encourages deeper diaphragmatic breaths that utilize full lung capacity. Mouth breathers might notice they yawn or sigh a lot – the body’s attempt to correct an oxygen deficit[30]. Over time, improper breathing can keep the body in a slight “fight or flight” state, raising stress hormones and heart rate. Some mouth breathers even develop a habit of breathing through the chest and neck muscles (instead of the diaphragm), which can cause tension and poor posture (forward head position).
Dry mouth, gum disease and cavities: Normally, nasal breathing preserves moisture in the mouth. Breathing through your mouth dries out your saliva, which is problematic because saliva protects your teeth and gums. Mouth breathing at night often leads to dry mouth, which in turn promotes bad breath and tooth decay. Saliva neutralizes acids and washes bacteria; without enough of it, bacteria thrive. Mouth breathers may experience more cavities and inflamed gums (gingivitis) as a result[2].
“Mouth breather face” in kids: As detailed earlier, children who chronically mouth-breathe can develop long-term skeletal changes: long face, small chin, crooked teeth, etc. This isn’t just an appearance issue – it can predispose them to breathing issues and orthodontic problems that require correction later. For example, a narrow palate from mouth breathing can make the nasal airway smaller, contributing to ongoing congestion and sinus issues, as well as speech articulation problems. It becomes a self-perpetuating cycle if not addressed.
Reduced athletic performance: If you’re breathing through your mouth during exercise, you may tire out faster. Without the nose’s efficiency and nitric oxide boost, mouth breathers often need to take more breaths to get the same oxygen, limiting endurance. You might also notice more side stitches or cramps (as over-breathing can mess with CO₂ levels), and simply feel more winded. Training yourself to nasal-breathe during workouts can increase your aerobic capacity and even lower your perceived effort[5].
Weaker immunity and ENT problems: As mentioned, mouth breathing bypasses the nasal immune filter. Mouth breathers may have more frequent sore throats, coughs, and colds. Children who mouth-breathe often have enlarged tonsils or adenoids (sometimes as a cause and effect of mouth breathing)[31][32], which can lead to chronic sinus and ear infections. There’s also evidence that mouth breathing (through reducing nitric oxide and drying airways) can increase risk of respiratory infections and even asthma. One research review noted higher rates of malocclusion and certain ENT issues in mouth-breathing kids[33][34].
Speech and swallowing issues: An open-mouth posture can affect tongue positioning and swallowing mechanics. Some mouth-breathing children develop a tongue-thrust (pushing the tongue forward against teeth when swallowing or speaking) due to the low tongue posture. This can contribute to lisps or other speech impediments, and further dental misalignment. Myofunctional therapists (specialists in oral muscle therapy) often work with mouth breathers to retrain proper swallowing and speaking patterns.

It’s clear that mouth breathing is more than just a quirk – it can degrade quality of life. A mouth breather often wakes up feeling unrested, with a dry mouth and sometimes a headache from oxygen drop. By afternoon they may struggle to concentrate (as the brain isn’t optimally oxygenated). If this sounds familiar, it’s worth taking steps to break the habit.

Mouth Breathing in Children: Why Early Intervention Is Key

For kids, nasal breathing is crucial for proper growth. According to the Cleveland Clinic, a child who consistently breathes through the mouth can even experience changes in their pituitary gland’s release of growth hormone, possibly stunting their growth[31]. That is, the same airway obstruction causing mouth breathing might also be disrupting normal deep sleep cycles when most growth hormone is produced. While mouth breathing itself isn’t directly “stunting” the child, it’s often a sign of underlying issues (allergies, swollen adenoids, etc.) that can affect overall health and development if left unaddressed[35].

Facial growth is most rapid in childhood – about 60% of facial development is done by age 4, and ~90% by age 12[36]. This means habits in those early years have a huge influence on the final outcome. A toddler naturally has a round, well-proportioned face. If that toddler starts mouth breathing (due to, say, chronic allergies or a thumb-sucking habit that promotes open-mouth posture), their facial bones will begin adapting to that posture. By the time they are a teenager, the differences can be dramatic, as we saw with examples like the boy who developed a long face in just a few years when his nose got chronically congested[18].

The developmental consequences go beyond appearance. A child who can’t breathe properly through the nose often can’t sleep deeply – leading to attention issues and hyperactivity misdiagnoses[29]. They might also have trouble keeping up in sports due to lower endurance. If large tonsils or adenoids are the cause, they may struggle with chronic ear infections or sinusitis. And of course, if their jaws grow improperly, they may require extensive orthodontic work (braces, palate expanders) in adolescence to fix the crowding and misalignment.

Pediatric dentists and ENTs therefore urge parents: pay attention to how your child breathes. If you notice your kid always has their mouth open, snores at night, or has difficulties chewing/swallowing, don’t dismiss it. These could be signs of airway obstruction or habit that need correction. Simple measures like addressing allergies, removing oversized tonsils/adenoids, or encouraging nose breathing can spare your child from a lot of issues down the road. In some cases, a specialist may recommend myofunctional therapy – essentially “physical therapy” exercises for the mouth and facial muscles to train a proper tongue posture and lip seal. Remarkably, myofunctional therapy and breathing retraining have shown great success. Kids as young as 5 or 6 can learn to keep lips closed and tongue on the palate through games and exercises. Over a few months, parents often see improvements: less snoring, better focus, and even changes in facial development. For instance, one before-and-after series from a speech therapy center showed a child’s face becoming visibly more balanced after therapy – her chin muscles relaxed, her bite improved, and her lips could stay closed at rest, all thanks to establishing nasal breathing and correct tongue position[37][38].

In short, early intervention is key. As soon as mouth breathing is identified in a child, tackling it can help ensure they grow into the healthiest (and most symmetrical) version of themselves. It’s much easier to guide a growing face than to fix things after growth is complete.

How to Fix Mouth Breather Face and Breathe Better

If you’ve been breathing through your mouth for years, don’t worry – it’s possible to retrain yourself to be a nose-breather. Here are some strategies and tips to help you or your child make the switch:

Instantly Expand Nasal Airways with Nasal Dilator: If you need extra help keeping your nose open, consider nasal dilator products. One innovative option is the Intake Breathing nasal dilator – a small external magnetic strip system that physically widens your nasal passages.

Unlike traditional nasal strips, which stick to your nose and can fall off, Intake uses adhesive tabs on the outside of your nose and a magnetic band to gently pull the nostrils open. This can dramatically increase airflow through the nose, making it easier to breathe during exercise or sleep. (Intake was originally designed for athletes to maximize nasal breathing during intense training.) Many users report it reduces snoring and mouth breathing by mechanically unlocking their nasal capacity. It’s a drug-free tool that might be worth a try if congestion or narrow nostrils are your issue. Even a simple over-the-counter nasal strip can help some – anything that encourages you to keep that mouth closed is beneficial. Just remember that, as Dr. Huberman noted, ultimately the goal is to rely on good habits rather than gadgets[20]. Use these tools as training wheels, while you build the habit of nasal breathing.
Practice Nose Clearing Exercises: Often, the nose adapts to being unused by feeling stuffy. Simple breathing exercises can help open your nasal passages. One popular technique from the Buteyko method is the “nose unblocking exercise”: take a normal breath in, exhale normally, pinch your nose and hold your breath for as many seconds as you can (within reason), then release and breathe through the nose again[42]. This breath-hold can momentarily increase CO₂ and nitric oxide, which dilate nasal blood vessels. Repeat a few times and you might find your nose is less stuffy. In one study, asthma patients who practiced nasal breathing exercises saw a 70% reduction in nasal congestion and snoring symptoms[43] – a huge improvement that helped them comfortably switch to nose breathing. Even something as simple as alternating hot and cold washes or using saline nasal spray before bed can reduce nasal stuffiness.
Conscious Habit Training: During the day, make a conscious effort to keep your lips gently sealed and breathe through your nose. It might help to place little reminder notes or set phone alerts every hour to “check your breathing”. When exercising, try to do as much of it as possible nasally – start with light exercise and nose-breathe, then gradually increase intensity while keeping your mouth shut. This will train your body to handle CO₂ and improve your nasal airflow over time. Remember Nestor’s advice: the nose is a “use it or lose it” organ[7][44]. The more you use it, the more it will open up. Yes, the first few weeks might feel tough (you could feel “air hunger” or panic initially), but stick with it – many people report that after a month of consistent nasal breathing practice, they can’t imagine going back. Endurance and overall energy often increase as your body adapts[44][45].
Night-time Mouth Taping: One of the simplest yet most transformative hacks for night mouth breathing is mouth taping. This involves placing a small piece of porous surgical tape (like 3M Micropore paper tape) over the lips before sleep to gently keep the mouth closed. It’s not as scary as it sounds – you use just a small strip, and it will naturally loosen if you cough or need to open your mouth. James Nestor swears by this, noting that it “was absolutely transformative to my sleep” and that thousands of people have found it to be the biggest health “hack” they’ve tried[46][47]. By forcing nasal breathing at night, you can vastly improve sleep quality and wake up without dry mouth. Important: if you have severe nasal obstruction or sleep apnea, talk to a doctor before trying mouth taping. But for most people, it’s a safe, cheap trick to encourage nose breathing. Give it a few nights to get used to – many report snoring less or not at all once they tape at night.
Chew Your Food (Seriously): This one might surprise you, but chewing is actually an important part of proper oral and airway development. Soft modern diets that require little chewing are linked to smaller jaws and more crowding of teeth (hence the need for braces). Chewing stimulates bone growth in the face and keeps jaw muscles strong. So, make a point to include some tougher, chewier foods in your diet – think raw veggies, nuts (if appropriate), whole fruits, jerky, sugar-free gum, etc. Dr. Huberman in his chat with Chris Williamson emphasized that eating tough foods helps develop the mouth, jaw, and even has downstream benefits on metabolism[48][49]. For growing kids, sufficient chewing is critical for widening the palate. So don’t cut everything into mush – let those jaws work (within reason and safety). It’s like natural weightlifting for your face.
Myofunctional Therapy and Orthotropics: If mouth breathing has already affected your or your child’s facial development, consider seeking a specialist who can guide oral posture correction. Myofunctional therapists can teach exercises to strengthen the tongue and lip muscles and establish a correct resting posture (tongue on palate, lips closed, breathing through nose)[50]. Orthodontists trained in orthotropics (a field pioneered by Dr. John Mew) focus on guiding jaw growth by correcting oral habits. They might use devices to expand the palate or correct tongue posture. These interventions, combined with consistent nasal breathing, can sometimes improve facial structure even in teen years or adulthood. Cases exist of teens who improved its jawline and nasal breathing and saw their once-receded chin become more prominent naturally, avoiding jaw surgery. While results vary, the consensus is that it’s never too late to benefit – our facial bones continue to remodel throughout life to some degree, especially with muscle forces applied.
Stay Consistent and Patient: Switching from mouth breathing to nasal breathing won’t happen overnight. Be patient and celebrate small wins – like getting through the night without mouth-breathing, or noticing you didn’t have to reach for water because your mouth wasn’t dry. If you slip up (e.g. catch yourself mouth breathing when focused on work), just reposition and carry on. Over weeks and months, your body will adapt. Many former mouth breathers report that after sustained nasal breathing practice, they naturally start breathing through the nose even under stress, and if they try mouth breathing again, it feels uncomfortable. That’s when you know the habit has truly changed.

In summary, mouth breathing is a bad habit with serious consequences – but it can be fixed. By prioritizing nasal breathing, you’ll not only support more harmonious facial development and dental alignment, you’ll sleep better, feel more energetic, and maybe even avoid illness. As one final motivator: a recent study even suggested that people find faces of nasal breathers more attractive on average than those of habitual mouth breathers[22][51]. Beauty and health often go hand in hand, and breathing is no exception. So do your face (and body) a favor – close that mouth, open that nose, and take a deep, invigorating breath through your nostrils. Your future self will thank you for it!

Sources:

Cleveland Clinic – Mouth Breathing: Symptoms, Complications & Treatment[31][29]
Palmetto Smiles (Dr. J. Wallace) – Effects of Mouth Breathing on Facial Growth[2][52]
James Nestor, Breath: The New Science of a Lost Art – Interview in BBC Science Focus[5][46]
Miles Kimball blog – James Nestor on How Bad Mouth Breathing Is (summary of Breath)[17][24]
Patrick McKeown & Dr. John Mew – Buteyko Clinic: Mouth Breather Face Article[16][36]
Dr. Andrew Huberman on Modern Wisdom Podcast (Ep. 700, 2023) – Conversation on mouth breathing[20][22]

[1] [29] [31] [32] [35] [39] [40] [41] Mouth Breathing: Symptoms, Complications & Treatment

https://my.clevelandclinic.org/health/diseases/22734-mouth-breathing

[2] [30] [52] Effects of Mouth Breathing on Facial Growth | Palmetto Smiles of Beaufort | Dentist in Beaufort, SC 29907

https://www.palmettosmilesofbeaufort.com/effects-of-mouth-breathing-on-facial-growth/

[3] [4] [5] [6] [7] [9] [44] [45] [46] [47] Mouth-breathing: Why it’s bad for you and how to stop - BBC Science Focus Magazine

https://www.sciencefocus.com/the-human-body/mouth-breathing

[8] [10] [17] [24] [25] [28] James Nestor on How Bad Mouth Breathing Is — Confessions of a Supply-Side Liberal

https://blog.supplysideliberal.com/post/2020/7/14/james-nestor-on-how-bad-mouth-breathing-is

[11] [12] [13] [14] [15] [16] [18] [19] [27] [36] [42] [43] [50] Mouth Breather Face: Can Mouth Breathing Face Be Reversed? - Buteyko – Buteyko Clinic International