Mewing: does it work? Jaw, jawline, before and after

You may have come across mewing on TikTok or YouTube: keeping your tongue pressed against the roof of your mouth to get a stronger jaw and a sharper "jawline". It is a fair question and it deserves an honest answer, without mockery and without promises. This page sums up what is taught in the university diploma (D.U.) in orthodontics, in the reference textbooks (Boileau) and in published studies. It is here to inform you; it does not replace an examination: every face is different.

What is mewing?

The word comes from the family name of a British dentist who started "orthotropics", an approach that puts the position of the tongue and lips at the centre of facial growth. The version that circulates online: the whole tongue, tip included, resting against the palate, lips closed, breathing through the nose. The instructions vary from one video to the next: a simple resting position for some, strong and prolonged pressure for others.

Researchers are now studying the trend. A study of online content about "looksmaxing" (practices aimed at improving one's appearance) found mewing among the topics followed, with a mostly male audience (about 74% of mewing content). It describes messages using pseudo-scientific language (language that sounds like science without being science) that make risky practices seem harmless (Grillo et al., 2026, PubMed). Another study, of more than 8,000 comments on a looksmaxing forum, shows that the community pushes its members to change their bodies, including through mewing; the authors consider that this climate harms the health of the young men who take part (Halpin et al., 2025, PubMed).

Wanting to feel good about your face is normal, at any age. What matters is knowing what is proven and what is not.

Why the tongue really matters

The idea behind mewing is not absurd: the position of the tongue is one of the foundations of orthodontics.

Teeth between the tongue and the cheeks

The D.U. courses describe a "corridor": the teeth line up between the tongue, which pushes outwards, and the lips and cheeks, which push inwards. Two points match the intuition behind mewing:

the position of the tongue at rest matters more than the moment you swallow;
according to Boileau, weak muscle forces applied for a long time, at rest, can change the shape of the dental arches during growth.

When the tongue stays low, the cheeks act without a counterweight and the upper jaw may stay narrow. Mouth breathing, a low tongue and swallowing "like a baby" (atypical swallowing) often go together.

Genes or functions?

According to the courses, the face grows under the influence of genes, hormones and the environment, including functions (breathing, swallowing, chewing). The researcher who most strongly defended the role of functions himself acknowledged that most scientists attributed growth mainly to genes, and spoke of a controversy (Moss, 1997, PubMed). The D.U. teaching asks for these ideas to be presented with caution, for lack of solid evidence. Mewing takes the idea that "function shapes the face" to its extreme; orthodontics sees it as one factor among others.

Retraining already exists

Correcting the position of the tongue is part of dental care, especially in children. The courses place this retraining after treating any obstacle (a blocked nose, a tongue-tie) and after retraining breathing. These rules, however, rely mainly on the opinion of experienced authors, the weakest level of evidence.

Does mewing work? What studies say

On mewing itself: no controlled study

A search of PubMed, the large database of medical articles, for "mewing" and "orthotropics" (October 2026) finds no controlled trial: no study compares people who practise mewing with people who don't by measuring the jaw bones. There are opinion pieces and studies on the online trend. Any figure for "jaw gains" from mewing is therefore not based on any published study.

The tongue, the lips and breathing

A landmark article concludes that the teeth are held in place mainly by the resting pressures of the tongue and lips, and that breathing changes the position of the head, the jaw and the tongue (Proffit, 1978, PubMed). This principle concerns the position of the teeth, not the shape of the bone in an adult.

Researchers blocked the noses of young monkeys to force them to breathe through their mouths: their faces and teeth developed differently from those of the other monkeys (Harvold et al., 1981, PubMed). In a series of eight animals, the lower face became longer; some of the changes reversed after nose breathing was restored, with large differences from one animal to another (Vargervik et al., 1984, PubMed). So a disturbed function can change the growth of a young animal; this does not show that a voluntary posture changes a human face.

In children and teenagers

A review of 17 studies in young people aged 3 to 18 found a link between an open bite (the front teeth do not touch) and an abnormal way of swallowing, but no clear conclusion for a low tongue (Thijs et al., 2021, PubMed).
A review of 15 trials considers retraining of the mouth muscles in children promising, but the quality of the evidence questionable (Koletsi et al., 2018, PubMed).
In 18 children aged 6 to 10, with no comparison group, an appliance that supports the work of the tongue widened the dental arches, with no notable change in the bones (d'Attilio et al., 2026, PubMed).
A review of 10 studies on removing the adenoids and tonsils describes favourable effects on the teeth, clearer effects on the bones when the operation takes place before age 6, but no full return to normal: orthodontic treatment is often still needed (Singla et al., 2026, PubMed).

The common thread: in children, functions influence growth, especially early on and especially at the level of the teeth; the effect on the bones remains limited and variable.

Jawline and jaw exercises

For a more defined "jawline", jaw exercisers are also sold. In a report on two people who used one for three months, neither noticed any change; the authors point to possibly misleading advertising (Verma et al., 2024, PubMed). A small trial of facial exercises (18 people, 7 weeks), which assessed among other things the jaw contour, does not allow any conclusion that they work (De Vos et al., 2013, PubMed).

Child or adult: what is possible

In a growing child

According to the courses, the width of the upper jaw is set early, at around 5 to 7 years. But the order matters:

Treat the obstacle: a child who breathes through the mouth first needs a check-up with an ENT doctor (the ear, nose and throat doctor). Retraining with a blocked nose does not work.
Retrain with a professional: breathing from age 4 to 5, then the tongue and lips at around 8 to 9 according to Boileau.
Correct the shape if needed, for example with an appliance that widens the upper jaw (see our guide on dental braces).

According to Boileau, retraining alone is only enough for small problems, not for large mismatches between the jaws. Instructions seen online do not replace an examination or supervised retraining.

In adults

The D.U. teaching is clear: without growth, braces alone do not correct the jaw bones. If an active appliance cannot do it, there is no reason to expect more from a posture. A review also notes that bone adaptations linked to mouth breathing decrease once growth is over (Ding et al., 2025, PubMed). Keeping your lips closed and breathing through your nose is still a healthy habit, but it does not replace professional advice.

Mewing before and after: what are the photos worth?

"Before / after" photos shared online can be impressive. Yet very little is needed to transform a profile: head tilted up or down, chin pushed forward, lighting, distance, weight loss, or growth in a teenager. Dentists compare photos taken under the same conditions: same head position, lips at rest, same framing. A "before / after" taken without these rules proves nothing.

Is mewing risky?

No controlled study describes the side effects of mewing itself: so we cannot say it is dangerous in itself. Three reservations remain well founded:

At rest, the teeth are apart. At rest, the upper and lower teeth do not touch. Some versions of mewing add clenching of the teeth and forced pressure; yet the textbooks link clenching to jaw joint problems (pain, clicking, locking).
Delaying a consultation. This is the most concrete risk. Some problems are better treated early, such as a lower jaw that sticks out in a young child, or constant snoring. None of them can be solved by a posture exercise.
The online environment. The studies cited above describe communities where mewing sits alongside much riskier practices, presented as harmless. If the image of your face is causing you distress, talk to someone you trust or to a doctor.

When should you see a dentist?

A concern about your jaw or profile deserves an examination if you notice:

in a child, mouth breathing, snoring, a mouth that is often open;
lower teeth that sit in front of the upper ones, or a chin that sticks out;
side teeth that cross over, or a jaw that shifts to one side when closing the mouth;
front teeth that do not touch, or a tongue that slips between the teeth;
pain, clicking or locking of the jaw;
in an adult, a marked mismatch between the jaws.

According to the D.U. courses, there is no minimum age for a first consultation, as long as it does not automatically lead to treatment. The examination tells you what calls for monitoring, retraining, an appliance or, more rarely, surgery.

In practice

If you practise mewing, keep a relaxed posture: lips closed, breathing through your nose, teeth not touching.
Don't clench your teeth and don't force the pressure of your tongue.
Be wary of before/after photos and promised results: no study confirms them.
In children, mention any mouth breathing or snoring: the nose check-up comes first.
If your jaw, chin or teeth worry you, have them examined: you can book an appointment.

Frequently asked questions

Does mewing change your jaw?

No controlled study has shown this so far: in children, the position of the tongue acts mainly on the teeth, and in adults, without growth, even braces alone do not correct the jaw bones.

Can mewing give you a more defined jawline?

Nothing proves it: jaw exercisers and facial exercises have not shown a clear effect on the jaw contour, and before/after photos online are not taken under comparable conditions.

Is mewing dangerous?

No study describes its side effects; the reservations concern versions that clench the teeth or force the pressure, whereas at rest the teeth do not touch, and above all the risk of delaying a useful consultation.

Mewing or braces?

They do not answer the same question: a good tongue position and nose breathing are among the goals of treatment, but a mismatch between the jaws, crossed teeth or an open bite call for an examination by the dentist, case by case.