Mewing is a viral technique that’s supposed to change the appearance of your jawline. But there’s no evidence to suggest it’s effective.

Mewing is a do-it-yourself facial restructuring technique involving tongue placement, named after Dr. Mike Mew, a British orthodontist.

While the exercises seem to have exploded on YouTube and other websites, mewing itself isn’t technically new. In fact, proper tongue alignment is recommended by some orthodontists and other medical professionals as a way to define the jaw, correct speech impediments, and potentially alleviate pain from jaw-related issues.

Despite the hype, mewing has a lot of limitations and may not work like you might see on a YouTube video. If you have medical concerns about your mouth and jaw, you’re better off seeing a doctor for diagnosis and treatment.

At the heart of mewing is learning how to reposition your tongue into a new resting place. Supporters of the technique believe that, over time, your tongue position will change your overall facial features, most notably the jawline.

People also believe it may help alleviate jaw pain and provide relief from snoring. Mewing is supposed to work by making your jawline more defined, which can help shape your face and perhaps make it look thinner, too.

While Dr. Mew is credited with popularizing the technique on the internet, these exercises weren’t actually created by the orthodontist. A quick search on YouTube will lead you to videos of others who have tried the technique and have purportedly gotten results. (There are a few videos that debunk the craze, too).

Proponents of mewing also believe that it isn’t the exercise that changes your face, but rather the lack of mewing that can transform your jawline for the worse. It could even possibly provide corrective techniques for children with tongue posture issues that might lead to irregular bites and speech issues, as discussed in one study.

On the other hand, experts fear that individuals who are in need of surgery or orthodontic work might mistakenly try mewing instead to help fix any issues on their own.

YouTube videos, along with numerous before and after pictures, can sometimes persuade viewers into believing that mewing works. However, it’s important to remember that such sources aren’t always reliable.

Many of these online tutorials usually include several weeks or months of practicing mewing, rather than the required years. Additionally, images can be deceiving because of shadows and lighting. The angle at which the people in the photos position their heads can also make the jaw look more defined.

More clinical research is needed to determine the efficacy of mewing.

Mewing is the technique of flattening out your tongue against the roof of the mouth. Over time, the movement is said to help realign your teeth and define your jawline.

To properly mew, you must relax your tongue and make sure it’s entirely against the roof of your mouth, including the back of the tongue.

This will likely take a lot of practice, since you’re likely used to relaxing your tongue away from the roof of the mouth without giving it a second thought. Over time, your muscles will remember how to place your tongue in the correct mewing position so it becomes second nature. In fact, it’s recommended that you mew all the time, even when drinking liquids.

As with any DIY technique that seems too good to be true, there is a catch with mewing — it may take yearsto see results. Maxillofacial deformities are typically corrected with surgery or orthodontics, so you shouldn’t assume that you can quickly correct any issues on your own by mewing here and there.

One study looked at tongue resting positions to see if any muscle groups were engaged as a predictor of long-term memory. In this case, researchers found that the 33 people in the study didn’t exhibit any signs of altered muscle activity.

While not inherently dangerous, there’s not enough evidence available to support the mewing craze for defining your jawline. If you have any pains or cosmetic concerns in the jaw area, see your doctor to discuss treatment options.

You can still try mewing, but be prepared to find little to no results. Until mewing is properly researched as an orthodontic solution, there’s no guarantee that it will work.