What Is Mewing? What Orthodontic Evidence Actually Says
Mewing is everywhere on social media, usually with a promise attached: a sharper jawline, a more defined profile, sometimes a "fixed" bite, without braces or surgery. Patients and parents ask about it. This article explains what mewing is, what orthodontic training says about tongue posture and facial growth, and what the scientific literature actually contains. It is written by orthodontic practitioners, for colleagues and for anyone curious. It does not replace an examination: a personal question about your face or your bite deserves an orthodontist’s opinion.
What is mewing?
Mewing is a self-taught tongue posture exercise. In its usual online form, the whole tongue, including its back part, rests flat against the roof of the mouth. The lips stay closed, the teeth are lightly together or just apart, and breathing goes through the nose. Some versions add pressure, swallowing drills or neck posture cues. The goal, as presented online, is to change the shape of the face over time.
The name comes from the Mew family of British orthodontists. John Mew developed an approach he called orthotropics, which he described as growth guidance: treatment in growing children, with appliances, aimed at directing facial growth forward instead of downward, with tongue posture and lip seal at its center (Mew and Meredith, J Laryngol Otol, 1992). In a 2004 overview, he acknowledged that long-term oral posture cannot be measured with any precision, and argued for philosophical reasoning where evidence is missing or conflicting (Mew, Am J Orthod Dentofacial Orthop, 2004). His son Mike Mew later proposed "craniofacial dystrophy", a hypothesis linking an open-mouth posture, weaker chewing and a low tongue to a longer face and less room for the airway and the teeth (Mew, Br Dent J, 2014). It was presented as a possible syndrome, not as a tested finding.
Mewing is the online, do-it-yourself descendant of that idea, detached from any examination, any appliance and any follow-up. It later became part of "looksmaxing" (often spelled "looksmaxxing"), an online movement of mostly young men who try to improve their appearance, with the jawline as a central theme.
What orthodontists already know about the tongue
Mewing did not invent the idea that the tongue matters. Tongue posture, swallowing and breathing are standard topics in the university diploma (D.U.) orthodontic courses we base our content on. What follows comes from that teaching.
The normal resting tongue
According to the D.U. courses, physiological breathing is nasal and, at rest, the back of the tongue lightly touches the palate while its edges follow the teeth. In other words, the resting posture that mewing promotes is close to what orthodontic courses describe as normal. The difference lies elsewhere: in what is promised, and in who checks whether it applies.
The teeth sit in a muscular balance
Orthodontic teaching describes a "neutral zone" (Château’s dental corridor): the teeth align in a zone of balance between the tongue, pushing outward, and the lips and cheeks, pushing inward. Any imbalance of posture, volume or tone, especially of the tongue, can move teeth. The courses insist on one point that matters for the mewing debate: the resting posture of the tongue counts more than swallowing alone, because light forces applied for many hours a day act more than brief, stronger ones.
A low tongue, for example, leaves the cheeks unopposed, which is associated with an underdeveloped maxilla in width. Mouth breathing, a low tongue, an immature swallowing pattern and sucking habits often go together and can show up as a narrow upper jaw, an open bite or forward-tipped incisors. Our French articles on oral habits and dysfunctions (in French) and on anterior open bite (in French) go into the clinical detail.
Function and form: an old, honest debate
The idea that function shapes bone has a long history in orthodontics. Moss’s functional matrix theory holds that the soft tissues and spaces grow first and that bone follows. Our course materials teach it alongside genetic and combined theories. The functionalist hypotheses are, however, presented more confidently in teaching than the international evidence supports: they should be read as debated, with a limited level of evidence.
The same caution applies to mouth breathing. The EMC (the French medical and surgical encyclopedia) points out that mouth breathing coexists with every type of malocclusion, and even with normal occlusion, and that causality has not been demonstrated. The associations most often retained are a long face, a steep mandibular plane and an extended head posture.
Children versus adults: what growth allows
Whether tongue posture can influence bone depends heavily on whether the person is still growing.
In growing children
During growth, the maxilla grows at its sutures and by surface remodeling. According to Boileau, this membranous type of growth depends mainly on environmental factors, and therefore on treatment, whereas cartilage growth is mainly genetic. Timing matters too: in our course materials, the midline sutures that govern maxillary width are most active until about 5 to 7 years. Condylar growth also responds to function: according to Boileau, with the mouth open (mouth breathing), it tends to be directed further backward.
This is why orthodontists screen for breathing and tongue problems early, and why they follow a precise order:
- Remove the obstacle first: an ENT problem (adenoids, tonsils, allergic rhinitis, a deviated septum), a short tongue tie, a sucking habit.
- Then retrain function: nasal breathing first, then swallowing, tongue posture and speech, often with a speech therapist or myofunctional therapist.
- Then correct the shape if it is still needed, with appliances.
Retraining breathing before the nasal obstacle has been treated is a classic mistake listed in the courses. Ages vary between sources: nasal breathing education from 4 to 5 years, active myofunctional therapy around 8 to 9 years according to Boileau. Boileau also limits "function before form" to small anomalies: when the skeletal or dental problem is large, the shape is corrected first. And he notes that behavior is easier to correct than resting posture, and resting posture far easier than tongue volume.
In a child, tongue posture is a real clinical topic, managed within a diagnosis, in the right order, after checking the airway.
In adults
Average growth ends around 15 to 16 years in girls and 18 years in boys, with individual variation. Our course materials are clear on one point: without growth, orthodontics alone does not correct the skeleton, whether in the sagittal, vertical or transverse dimension. Adults are treated by dental camouflage, combined orthodontic and surgical treatment, or multidisciplinary care.
If appliances cannot reposition adult jaws, there is no biological basis to expect a resting tongue posture to do so. What can change is the posture held at a given moment: a profile photographed with the tongue pressed up and the head tilted is not a change in bone.
What does the scientific literature say about mewing?
We searched PubMed for "mewing" and "orthotropics" on October 14, 2026. The search returns 33 records, most of them unrelated (the cat-like cry of cri-du-chat syndrome, or authors named Mewing). The relevant records are commentaries, papers by John and Mike Mew, and recent studies of online looksmaxing culture. We found no controlled clinical study measuring the effect of mewing on the jaws or the face, in children or in adults. Claims that mewing reshapes the jawline are therefore not supported by controlled evidence, in either direction: the question has not been tested properly.
The closest item is a study by John Mew of 12 pairs of identical twins, one twin treated with orthotropics and the other with conventional fixed appliances, assessed 10 years later. A panel of 12 lay judges rated most of the orthotropics-treated twins as improved and most of the conventionally treated twins as less attractive; the dental results differed little (Mew, World J Orthod, 2007). This study concerns appliance-based treatment of growing patients by the method’s own author, in a small sample, with attractiveness judged by lay raters. It does not test mewing, and it does not test adults.
What does exist is research on related, better-defined topics:
- Mouth breathing and facial form in children. A 2021 meta-analysis of 10 observational studies found that mouth-breathing children had, on average, a more backward and downward rotation of the jaws, a steeper occlusal plane and narrower airways than nasal breathers (Zhao et al., BMC Oral Health, 2021). A 2026 meta-analysis of 13 studies found narrower upper arches and more posterior crossbites in mouth-breathing children (Lekvijittada et al., BMC Oral Health, 2026). These are associations, not proof that changing tongue posture reverses them.
- Treating the airway in children. A 2026 systematic review of 10 observational studies concluded that adenotonsillectomy supports favorable dentofacial adaptation, more clearly before age 6, but does not reliably achieve full skeletal correction, and orthodontic treatment is often still needed (Singla et al., Int J Pediatr Otorhinolaryngol, 2026). A 2025 meta-analysis of 7 non-randomized studies found low-quality evidence of a normalized lower incisor inclination after interventions to relieve mouth breathing, and no significant change in arch width in the primary dentition (do Nascimento et al., J Orofac Orthop, 2025).
- Supervised myofunctional therapy. A 2018 systematic review of 15 controlled trials in children found early orthodontic and myofunctional treatment "promising", but rated the quality of the evidence as questionable (Koletsi et al., Orthod Craniofac Res, 2018). An earlier review found only 4 eligible studies, all at high risk of bias, on myofunctional therapy as an adjunct to orthodontics (Homem et al., Dental Press J Orthod, 2014). A small 2026 randomized pilot study (8 children aged about 8 with anterior open bite) found short- to mid-term functional and occlusal improvements after supervised therapy focused on breathing and resting postures, and called for larger trials (Van der Straeten et al., Clin Oral Investig, 2026).
In short: in children, breathing and tongue function are associated with facial and dental form, and supervised therapy shows encouraging but weak evidence. None of this concerns unsupervised mewing in adults or shows a change in jawline.
Is mewing dangerous?
No published study has measured harms of mewing itself, so it would be wrong to claim it damages the jaws. The documented concerns are elsewhere.
The online context. A 2025 qualitative study of more than 8,000 comments in a looksmaxing forum found that the community encouraged men to substantially alter their bodies, citing mewing alongside leg-lengthening surgery, and exposed users to demoralization and encouragement to self-harm (Halpin et al., Sociol Health Illn, 2025). A 2026 analysis of social media content found that looksmaxing discourse relies on pseudoscientific language and community validation, and normalizes clearly dangerous practices such as "bonesmashing" (deliberately striking facial bones); mewing content was about 74% male in that sample (Grillo et al., J Stomatol Oral Maxillofac Surg, 2026). Mewing itself is not bonesmashing, but it often circulates in the same spaces.
False expectations and delayed care. From a clinical point of view, the main risk we see is indirect: a teenager who mews to fix a bite instead of being examined, or a child with nighttime mouth breathing and snoring whose airway is never checked. In children, persistent snoring, noisy breathing, restless sleep and daytime sleepiness or inattention are signs that call for a medical assessment, not an exercise.
Body image. A jawline is shaped by the skeleton, the soft tissues, body composition and age; chin prominence, for instance, develops as a secondary sex characteristic during growth. Faces vary, and a face that differs from an online ideal is not a disorder. If appearance concerns take up a lot of space in someone’s daily life, talking to a doctor is a reasonable step.
When to see an orthodontist
An orthodontic examination is worth it, rather than an online exercise, if:
- a child breathes through the mouth, snores, or keeps the lips apart at rest;
- the teeth do not meet at the front (open bite), or the upper teeth bite inside the lower ones (crossbite);
- the jaw deviates to one side, or there is jaw pain, clicking or limited opening;
- a thumb, finger or pacifier habit persists;
- you are an adult and want to know whether a bite or profile concern is dental, skeletal, or both.
For orthodontists, a mewing question is a good opening for a functional examination. Our French guide to interceptive orthodontics (in French) describes when and how to intervene in growing patients, and our guide to orthognathic surgery indications (in French) covers the adult skeletal cases.
In practice: a checklist
When a patient or a parent asks about mewing:
- Ask what they expect: a different jawline, a fixed bite, better breathing?
- Assess growth status: a growing child and an adult are not the same question.
- Examine function: nasal breathing tests, resting tongue posture, swallowing, lip seal, tongue tie, signs of sleep-disordered breathing.
- Rule out an airway obstacle before any retraining, with an ENT referral if needed.
- Explain what the evidence supports (supervised functional care in children, as part of a diagnosis) and what it does not (skeletal change in adults from tongue posture).
- Stay neutral on appearance: no judgment of the face, no promise of a result.
Frequently asked questions
Does mewing work?
There is no controlled study showing that mewing changes the shape of the jaws or the face. A relaxed tongue resting against the palate, lips closed and nasal breathing is close to what orthodontic courses describe as normal, so the posture itself is not absurd. But the promised results, especially a new jawline, have not been demonstrated.
Can mewing change your jawline as an adult?
Not according to current evidence. Once growth is complete, orthodontics alone does not change the skeleton; if appliances cannot do it, there is no basis to expect a resting tongue posture to do so. What may change in the moment is posture, of the head, neck and tongue, which alters how a profile looks in a photo without changing the bone.
Is mewing dangerous?
No study has measured harms of mewing itself. The documented concerns are the online communities it circulates in, which research links to pseudoscientific claims, dangerous practices like bonesmashing and harm to self-esteem, and the risk of delaying an examination when there is a real problem, such as mouth breathing or snoring in a child.
Mewing vs orthodontics: what is the difference?
Mewing is an unsupervised exercise with no diagnosis. Orthodontics starts with an examination, including breathing and tongue function, then treats in order: remove any obstacle, retrain function when indicated, correct the teeth and jaws with appliances, and use surgery for adult skeletal problems that orthodontics alone cannot correct. Tongue posture is part of orthodontic care, not an alternative to it.
With GS Ortho
In GS Ortho, the functional examination is part of the guided diagnostic studio in 12 boards: breathing, swallowing and parafunctions are recorded chairside, alongside the rest of the case. The prompts remain criteria, never decisions: the ENT referral, the timing of retraining and the appliance stay your choice. You can request an orthodontist’s opinion in one click from the case, and the data stays hosted at your practice. The GS Ortho interface is currently available in French.