Mouth tape and jawline: what the before and after photos leave out

Where the jawline claim comes from

Search "mouth tape jawline" and the side profile photos keep coming. Left image: soft chin, slack mouth. Right image: tight jaw, lips together.

The caption says 30 days of mouth tape, or 60, or "since I started taping and mewing."

The idea did not start with tape. It grew out of mewing, a tongue posture practice named after a British orthodontist, John Mew, who argued that where you rest your tongue shapes your face. Around 2019 it spread across YouTube and Instagram, then TikTok. Mouth tape got folded in as the night shift: keep the lips closed while you sleep, and the tongue is supposed to sit on the palate on its own.

Some of the underlying ideas come from a real body of research. That is what makes the claim sticky. There is a genuine link between mouth breathing and how a face grows.

The problem is who that research is about, and over what span of time. First, the part that is true.

What is established: mouth breathing and growing faces

Orthodontists and ear, nose and throat doctors have studied mouth breathing in children for decades. The results are fairly consistent.

A 2010 study in The Laryngoscope compared 116 pediatric orthodontic patients: 55 who breathed through the mouth because of nasal obstruction and 61 who breathed through the nose. The mouth breathers were more likely to show a lower jaw that had rotated down and back, a larger overjet, narrower dental arches and a posterior crossbite (49 percent versus 26 percent). The authors describe the pattern as a "higher tendency for clockwise rotation" of the growing lower jaw.

A 2021 meta analysis in BMC Oral Health pooled 10 controlled studies, 1,358 children aged 2 to 14. Children who breathed through the mouth had lower SNA and SNB angles, which means the upper and lower jaws sat farther back, and steeper vertical angles. The authors summarize it plainly: "the mandible and maxilla rotated backward and downward, and the occlusal plane was steep."

Clinicians have an old name for the extreme version: adenoid facies. A 2024 review in Frontiers in Public Health describes it as a cycle. Enlarged adenoids block the nose, so the child breathes through the mouth.

The lips and tongue then rest in the wrong place, the arches narrow and the face grows long. The narrowed airway makes mouth breathing more likely, and the cycle continues.

A 2022 review in the same journal adds that the type of blockage matters: adenoids tend to push the bite one way and tonsils another. Its bottom line is that "uncorrected mouth breathing can result in abnormal dental and maxillofacial development."

So the trend is right about one thing. How a child breathes really does correlate with how that child's face turns out. If you have a child who sleeps with an open mouth or has a constantly blocked nose, that is a reason to see a pediatrician or an ENT. It is not a reason to tape.

Why this is about children, over years

Read the studies above again and notice three words that keep showing up: children, growth, years.

Every one of those studies was done in children whose faces were still growing. The meta analysis capped its age range at 14. The adenoid facies review notes that adenoid enlargement peaks between 6 and 10 years old. The 2010 study ties the effect to critical periods of growth.

The mechanism is not that mouth breathing sculpts bone directly. It is that a growing skeleton grows around the forces on it, and an open mouth changes those forces every hour of every day for years.

That same 2024 review is clear about the other end of the age range. It states that mouth breathing has a "relatively minor effect on the maxillofacial bones of adult patients." The bones of an adult have finished the growth spurt that made them responsive in the first place.

There is one more thing the trend gets backwards. In children, the fix that the research supports is treating the blockage, usually with an ENT or an orthodontist, sometimes with surgery to remove adenoids, sometimes with a palate expander.

The reviews describe those interventions. None of them describes taping a child's mouth. The safety guides we read say tape is not for children, and we found no study of it in children.

Why adult bone does not change from a strip of tape

Adult facial bones are done growing. The exact age varies, but the plastic surgeon quoted by HuffPost in 2023 put it this way: "the facial bones develop through the teenage years and into young adulthood." After that, the jaw does not lengthen, the palate does not widen, and the chin does not move forward because your lips were closed at night.

Bone in adults does remodel, but slowly, in response to heavy and repeated load, the way a tennis player's serving arm ends up denser. The load from resting your lips together is close to zero. Mouth tape adds nothing to it. The tape holds skin, not bone.

The American Association of Orthodontists said as much about mewing in January 2024. Its president stated: "there's no scientific evidence to support its claims of reshaping the jawline." The association also listed what it has seen in patients who push hard on tongue posture routines: loosened teeth, bite problems and speech changes.

If pressing your tongue against your palate for hours a day does not move adult bone in a good direction, keeping your mouth closed for eight hours at night will not either.

None of this says adults cannot change their jawline. Weight loss, orthodontic treatment, surgery and time all do. A strip of tape does not. If your jaw looks different after a month of taping, something else moved.

What can change overnight, and why it shows in photos

Here is the honest part that the trend gets half right. Some things about your face really can look different in the morning, and a few of them are affected by how you sleep. They are just not bone.

Morning puffiness is real. When you lie flat for hours, fluid that gravity normally pulls down settles in the loose tissue of the face, especially around the eyes and cheeks. Medical News Today lists this fluid shift along with salty food, alcohol, allergies and hormones as the main reasons a face looks softer at 7 a.m. than at noon.

The puffiness usually fades within an hour or two of being upright. A "before" photo taken on waking and an "after" photo taken in the afternoon will show a sharper jaw with no tape involved.

An open mouth changes your soft tissue posture too. When the lips part, the lower jaw drops, the muscles under the chin relax and the skin along the jaw goes slack. Close the lips, set the teeth lightly together, and the same face looks tighter.

Mouth breathers who start taping may also spend more of the day with the lips together, out of habit. That is a posture change, and it is visible. It is also reversible in one second, which tells you it is not structure.

Dry mouth and a dry throat are common after a night of open mouth breathing. Some people wake up looking and feeling a bit drained. If taping means you wake with lips less chapped and a less dry mouth, you may look more rested in a photo. That is comfort, not anatomy.

If you feel that your face looks better after taping, that impression may be true. It is worth knowing which of the reasons above explains it.

Posing, lighting and the camera

Even with no puffiness and no posture change, two photos of the same face can look like two different people. Cosmetic surgeons know this, which is why they write photo protocols.

A 2021 study in Aesthetic Plastic Surgery photographed 51 people under standardized conditions, changing only the angle of the light: straight on, 30 degrees and 60 degrees. Twenty seven blinded raters from six countries scored the photos.

At 60 degrees, the same faces were rated less attractive, and at both 30 and 60 degrees the raters guessed a higher body weight from the face alone. Nothing about the people changed. Only the lamp moved.

Now think about what a typical before and after post does with far less discipline than a lab:

• The before photo is taken face on, under a ceiling light, with the chin level or slightly down. The after photo is taken from the side, near a window, chin pushed forward and up.
• The before is unposed and often unflattering by design. The after is the twentieth try.
• The before is on a phone from a year ago. The after is on a newer camera, sometimes with a portrait mode that sharpens edges.
• The person has lost weight, grown a beard, started lifting, or simply learned to hold the jaw forward for the camera. Any of those will outrun tape.

None of this means the poster is lying. Most people believe their own photos. It means a two image comparison from one person, taken under conditions they chose, cannot tell you what caused what.

What the evidence does support

The article on this site titled "Does mouth tape work" goes through the evidence in full, so this section stays short.

The studies that exist are small and short. A 2022 study of 20 adults with mild sleep apnea used a short strip of 3M tape over the lips for one week and measured a drop in median breathing events, from 8.3 to 4.7 an hour. A 2015 pilot in 30 patients used a porous patch and saw a similar pattern. Both were in a narrow group, both lasted days, and neither had a control group.

A 2025 systematic review in PLOS One went through 10 studies and 213 patients, and rated all 10 as poor quality. It found a meaningful change only in mild disease and warned of a "potentially serious risk of harm for individuals indiscriminately practicing this trend." A separate 2025 scoping review in the American Journal of Otolaryngology looked at 9 studies alongside 50 TikTok videos and called the literature "markedly heterogeneous."

Neither review found a study that measured facial appearance, jawline or bone.

What the research does support is narrow: for adults who breathe well through the nose, a strip of tape can keep the lips together during sleep, and in small studies of mild cases that came with fewer measured breathing events. That is the entire evidence base. Jawline is not in it.

How to read before and after content

You do not have to dismiss every transformation post. You just need a few questions to ask before you believe one.

1. Same time of day? Morning fluid alone can account for a softer before.
2. Same angle, same light, same distance? If the head is turned or the chin is raised in one photo, stop there.
3. Same body weight? Ask, or look at the neck and the shirt collar. A few pounds off the face reads as jawline.
4. Same expression? Lips together and teeth lightly closed will tighten any jaw.
5. What else changed? New beard, new haircut, new camera, new workout habit.
6. Is anyone selling something? A jawline claim next to a checkout button is marketing, not evidence.
7. Is it one person? One person is a story. The studies above are hundreds of children, and they still could not say much about adults.

If a post passes all seven, it is still one person under conditions they chose. That is fine as a story. It is not a reason to expect your bones to move.

A note on safety

Mouth tape is a comfort product for people who already breathe well through the nose. It is not a face tool and it is not a treatment. If you try it for the lip habit, try it for that reason and no other.

Do not use mouth tape if you cannot breathe comfortably through your nose, if you have a cold or blocked sinuses, after alcohol or sedatives, if you have been told you have a breathing disorder during sleep, or if you are unsure. It is not for children. Ask your doctor first.

If the reason you are interested in taping is a child who breathes through the mouth, the research is on your side about taking it seriously. The next step is a pediatrician or an ENT, not tape. And if what you want is a sharper jawline, the honest options are the ones that were always there: body weight and posture, or an orthodontist's opinion if it matters to you.

Stillseal makes a strip with a slit in the middle so you never feel sealed in. It is built for one job, keeping lips together at night in comfort. We do not claim it changes how your face looks, because nothing in the research says a tape can.

Sources

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