What Is Mewing? Experts Weigh In On This Trick to Define Your Jawline

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Another day, another TikTok trend — only this time, the latest fad has actually been around for decades. Joining the ranks of other blast-from-the-past crazes such as low-rise jeans, pucca shell necklaces, and butterfly clips, mewing — the practice of changing your tongue position to strengthen and define your jawline — is the latest example of "what's old is new again."

Unlike the other trends topping social media charts, however, mewing is not necessarily as harmless as donning a claw clip or attempting to pull off brown lipstick. Ahead, experts break down everything you need to know about mewing and whether it's all Gen Zers claim it's cracked up to be.

What Is Mewing?

The practice of mewing is named after its reported founder, John Mew, a 93-year-old former orthodontist from the U.K. "He believes children can achieve straighter teeth and better breathing habits using techniques like mewing, arguably instead of traditional treatments like orthodontics or surgery," says Rhonda Kalasho, D.D.S., a Los Angeles-based dentist.

For years, Mew practiced what he coined "orthotropics," focusing on altering the jawline and face shape of his patients through facial and oral posture and exercises. But, in 2017, he was stripped of his dental license by the General Dental Council in the U.K. "on grounds of misconduct for publicly denigrating the traditional practices of orthodontic tooth movement," according to an article in the Journal of Oral and Maxillofacial Surgery.

At its most basic, mewing is a technique that involves changing your tongue's placement to improve breathing and, according to the many mew-ers on the internet, create a more defined-looking jawline. Mewing is all about "retraining the resting tongue position" or tongue posture, according to the same journal article. "When resting, patients are instructed to seal their lips and press their tongue against the posterior hard palate [roof of the mouth] as opposed to on the floor of the mouth," notes the article. Maintaining proper — vs. slumped — posture is also key.

If it feels weird, that's likely because your tongue might normally rest at the bottom of your mouth instead of against the roof of it. But, per the Journal of Oral and Maxillofacial Surgery, the more you practice mewing, the more you can become accustomed to this new tongue placement so that it ultimately becomes your tongue's instinctual resting position. The goal is "to increase the cross-sectional area, which provides 1) space for the teeth to align naturally, 2) a huge increase in tongue space," which is supposed to improve swallowing, breathing, and facial structure, according to the London School of Facial Orthotropics, (FWIW, the school was founded by Mew, despite his work being "mostly discredited" and considered by orthodontic researchers as straight-up "wrong," according to The New York Times Magazine. Needless to say, whether or not mewing actually yields those results, however, is iffy at best.

But over on TikTok, fans of the technique seem fairly confident that this tongue exercise does leave them with more defined jawlines. Take, for example, a TikTok user who "literally thought the only option left [to give her jawline shape] was fillers" until she tried mewing and it "changed her face," she claims. Need not forget that you can't trust everything on the internet.

So, Does Mewing Actually Work?

It's important to note that mewing as it's being shown on TikTok isn't exactly what Mew intended. The mew-ers of the internet seem less concerned with straighter teeth and better breathing and more focused on achieving a certain aesthetic — even just for a 60-second video. "I would think there is only a very small population that's interested in long-term orthodontic movement through the act of mewing," says Ryan Higgins, D.D.S., a California-based dentist. "Most young people are just trying to make their selfies look better," he adds.

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It's almost as if modern-day mewing is "something you can do to take a better picture without the help of social media filters from sites such as Instagram, Snapchat, and TikTok," as described by Higgins. But like a filter, the effects of mewing are fleeting. "Sure, manipulating your facial muscles to change the shape of your appearance can work for a very temporary amount of time," says Higgins. "Bodybuilders do it every time they flex on stage. However, as soon as you relax your taut muscles, your soft tissue will return to its resting position and thus makes mewing very temporary as a means to reshape the jawline and eliminate a 'double chin,'" he continues.

Even if you practicing mewing regularly, any jaw-defining results will likely still be ephemeral. What can last, however, are the lingering side effects of mewing. "The technique is based on the strengthening of certain facial muscles. Therefore, if you stop mewing, the effects could dissipate," explains Kalasho. However, mewing is not without its risks, as it requires you to keep your teeth touching throughout the day, potentially causing a lot of "teeth wear" and cracks in the enamel, adds Kalasho. What's more, if done incorrectly, mewing "can cause pain in the back of the neck, in the mouth, and you can perhaps cause misalignment of your teeth," she warns.

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But what about all the so-called proof of more defined jawlines on TikTok? Experts concede that repositioning your tongue might very well define your jaw for the moment, but overall, there's "no scientific evidence to back this practice," according to Jeffrey Sulitzer, D.M.D., the chief clinical officer at SmileDirectClub.

Should You Try Mewing?

If you're looking for straighter teeth or sounder sleep (thanks to better breathing), it's best not to take matters into your own hands and instead consult an actual medical professional. A dentist or orthodontist can help determine the best course of action for conquering crooked teeth, misalignment, or other mouth woes.

And even if you're just hoping for a slightly more defined jawline, it's important to seek out expert advice vs. DIY, emphasizes Sulitzer. "I would not recommend this practice [of mewing] to my patients, and especially not without the guidance of a dentist or an orthodontist," he says. Other pros echo that sentiment. "Mewing is fine for a picture here and there, but if you're trying to change the shape of your face, you want to make sure you're doing it correctly," says Zainab Mackie, D.D.S., aka "Your TikTok Dentist." "Self-diagnosis is always dangerous. This is why it's best to consult a physician or dentist and make sure you receive guidance from them," she adds.

TL;DR — Yes, mewing has the potential to sharpen the jawline and "eliminate the 'double chin' for your perfect selfie," says Higgins. But once the flash goes off, let your mouth and muscles relax. And if you still have any cosmetic or medical concerns, use your tongue for talking...to a dental professional, who can give legit, evidence-backed advice.