What mewing does not do in adults

There are no studies, not weak ones

There are no good clinical trials showing that tongue posture changes adult facial bone geometry. What you will find instead is before-and-after photos and testimony, and neither is evidence. This is why BecomeTen's plan always marks mewing as having no studies rather than stretching an unrelated paper to cover it. A rater that cites a real source for sunscreen and a fake one for tongue posture would be worthless on both.

What helps, and what is dangerous

Head and neck posture changes how the jaw line reads, both in photos and in person, and that is legitimate. What does not work — and what is dangerous — is bone smashing, striking the mandible or the cheekbones, and any related forum advice. Damaging tissue is not remodelling it. BecomeTen refuses to recommend it, and the refusal is written into the prompt, not left to the model's judgement.

What does mewing claim?

The claim, in its common form, is that resting the whole tongue against the roof of the mouth, keeping the lips closed and breathing through the nose will, over months or years, push the maxilla forward and upward, widen the palate, lift the cheekbones and sharpen the jaw. Stronger versions add that it can correct a recessed chin or reshape the eye area by moving the orbital bones.

Some of this is borrowed from a real field. Orthodontists and myofunctional therapists do work with tongue posture and oral habits in children, whose facial bones are still growing and whose sutures have not fused. The looksmaxxing version takes a paediatric idea and applies it to adults, where the sutures of the midface have closed and the mandible has finished growing. That extension is the part with no support.

What would count as evidence, and why is there none?

Evidence for a bone claim would look like this: a group of adults assigned to the practice and a comparable group not assigned, imaging of the skull before and after a defined period, measurements taken by people who do not know which group each person was in, and a difference larger than the measurement error. That is a modest bar. Orthodontics clears it routinely for appliances that apply continuous, measurable force.

Nothing like it exists for mewing. The reason is not a conspiracy; it is biology. Adult bone remodels in response to sustained mechanical load, and the tongue at rest does not apply anything close to the force an orthodontic appliance does, nor in a direction that would move a fused maxilla. Anyone who ran the trial would expect a null result, which is why nobody funds it and why the claim survives only in forums.

• No randomized trial in adults.
• No before-and-after imaging study in adults with blinded measurement.
• No mechanism that explains adult bone movement from resting tongue pressure.

Why are before-and-after photos not evidence?

Because almost everything that makes a jaw look different in a photograph is not bone. Camera angle first: a chin tilted a few degrees down sharpens the jaw and shortens the lower third, and a chin tilted up softens both. Lighting second: side light throws the jaw border into shadow and makes it read as an edge; flat light erases it. Body composition third: two years between photos is enough for a young man to lose facial fat with no change in habit, and enough for anyone to lose or gain several kilograms.

Add facial hair, a haircut that changes the visible width of the face, a better phone, and the fact that people post the pairs that look impressive and not the ones that do not. A before-and-after can be entirely honest and still show nothing about bone. This is the exact reason BecomeTen grades every photo for lighting, angle and sharpness and withholds a comparison when the two are not comparable.

The body-fat row deserves the most weight because it has the most evidence behind it. A 2009 study in Perception found that facial adiposity, the amount of fat visible in a face, is a cue observers use when they judge health and attractiveness, and a 2010 study in the same journal showed that weight can be read reliably from a face image, from cues such as the width of the cheeks against the width of the jaw. Those are exactly the cues a mewing before-and-after appears to change. Nobody needs tongue posture to explain them; a modest change in body composition does it, and it does it on the same timescale as the photos. The jawline score tool reads the lower third from one photo in the browser and says how much of what it sees is likely fat, posture and camera height rather than bone, which is the honest version of the comparison people are trying to make.

The posture point, done honestly

Here is what is true. A forward head position folds the soft tissue under the chin and hides the jaw border; a neutral head position with the chin level unfolds it. People who start mewing usually also start paying attention to posture, closing the mouth and breathing through the nose, and those habits do change how the lower third reads in a photo and in a room. The effect is real and immediate and it has nothing to do with bone.

It is also fair to say that nasal breathing and a closed resting mouth are ordinary good habits with benefits beyond appearance. If mewing is the reason someone adopts them, fine. The error is attributing a posture change to skeletal change, then spending years waiting for a maxilla that is never going to move. Keep the habit; drop the expectation.

What BecomeTen's plan says about mewing

Every step in a BecomeTen plan carries one of four evidence levels: strong, moderate, weak or no studies. The AI model is not allowed to cite from memory; it may only attach sources from a curated library, and the server rejects any id that is not in it. There is no entry for mewing in the library, so if the plan mentions tongue posture at all it appears with the no-studies label and no citation.

In practice, the plan handles the jaw and chin area the way the evidence does. The workable traits are jawline definition, submental definition and maxilla support as it reads through soft tissue; the levers are body composition, posture and grooming. Gonial angle, ramus ratio and chin projection are tagged structural and the plan may not promise a fix for them. That split is the product's whole position on mewing, stated in the report rather than argued in a forum.