Mewing and Your Jawline: What the Research Shows
You've read the threads. Someone posts a before-and-after, the comments are split between "life-changing" and "that's just lighting," and nobody cites anything. Here's what the published literature says, as far as we could find it.
The short version
We searched PubMed for "mewing," "tongue posture training adults skeletal change," "myofunctional therapy adults jaw shape change," "tongue posture exercise effect on facial skeleton adults," "orofacial myofunctional therapy facial skeletal growth," "mewing tongue posture jawline social media orthodontics," and "myofunctional therapy randomized trial craniofacial growth children." We found no controlled study showing that deliberate tongue-posture practice reshapes the jaw or jawline in adults.
That isn't the same as a study proving mewing fails. It means the claim most people are making, that you can practice tongue posture and change your adult jaw, doesn't have controlled evidence behind it. If you're running a multi-year protocol on the strength of "it's probably fine," you should know that's the situation.
The study people point to
The strongest thing mewing advocates can reach for is a small controlled study on resting tongue posture. It compared 20 Class III subjects with 20 Class I subjects, with average ages of about 17-19. The authors reported: "Tongue posture is significantly lower in Class III subjects and is associated with the dentoalveolar characteristics of the maxilla and mandible."1
That's a real finding, and it's worth taking seriously for what it is. Resting tongue posture lines up with the shape of the tooth-bearing parts of the jaw. But it's a correlation, measured in 40 people. It doesn't show that changing your tongue posture changes your jaw. Maybe posture shapes the jaw. Maybe jaw shape shapes posture. Maybe something else drives both. This study can't separate those, and it wasn't designed to.
It also looked at dentoalveolar shape, meaning the tooth-bearing part of the jaw, which isn't the same as the jawline you see in a mirror. And it was a teenage-ish sample, not men in their mid-20s.
So the accurate summary is that there's a correlation in a small sample and no controlled evidence of an adult jaw changing from practice.
Why it feels more proven than it is
If the evidence is this thin, why does it feel settled? A social media analysis of looksmaxxing content, including mewing and bonesmashing, has an answer. It found that these practices make up "a significant online phenomenon with substantial reach and engagement, particularly among young men."2
The same analysis looked at the 100 most-engaged posts and identified four dominant narratives: self-improvement as empowerment, pseudoscientific legitimacy, community belonging and mutual validation, and risk minimization and normalization.2 In other words, promotion of these practices leans on science-sounding language, while risks get played down and the practices get treated as normal within the community.
You can see the pattern in any thread. Someone uses the vocabulary of anatomy, someone else backs them up, and the group's agreement starts to feel like data. Wanting to improve yourself is fine, and community is fine. Neither one counts as evidence that the method works.
What to actually do
None of this means you should shrug and give up on your face. It means putting your effort where there's some chance of a return.
Treat before-and-after photos with suspicion. Lighting, camera angle, weight change, age, and posture can all change how a jawline looks in a photo. If someone's "after" was shot from slightly below with hard side lighting, you're looking at a photography result. Try it yourself: take ten photos of your own face in five minutes, changing only the angle and light. You'll get a before and an after with no mewing involved.
If you're unhappy with your jaw or bite, get a proper assessment. See an orthodontist or an oral and maxillofacial surgeon. They can look at your actual structure and tell you what's realistic, which no protocol from TikTok or Reddit can do. Go in with a specific question: what bothers you, and what are the options?
Don't try bonesmashing or any other DIY force on your face. It's in the same content ecosystem as mewing, and the analysis above found risks get minimized there. Don't be the test case for a technique that's promoted with pseudoscientific language and has no controlled evidence behind it.
If something hurts or doesn't work right, get it checked. Jaw pain, trouble breathing or sleeping, or a bite problem are reasons to see a dentist or doctor, not to add more self-treatment. Some of the things people hope mewing will fix belong in that category. Get them assessed properly instead of spending months on a forum protocol.
Can you still do it?
Nobody's stopping you from paying attention to where your tongue rests. The correlational study above gives you a reason to find the topic interesting, and there's no controlled evidence it does anything for your adult jawline. If you try it, keep the expectation honest, keep it cheap, and don't let it replace a real consult if you have a real concern.
The gap between "associated with" and "causes" is the whole story here. Until someone runs the controlled study in adults, that gap is where the hype lives.
Sources
- PMID 22467568 — “Tongue posture is significantly lower in Class III subjects and is associated with the dentoalveolar characteristics of the maxilla and mandible.”
- PMID 42674114 — “The data demonstrate that looksmaxxing practices constitute a significant online phenomenon with substantial reach and engagement, particularly among young men.”