That extra fullness under your chin when you talk is usually caused by muscles in your neck and jaw contracting during speech, pulling skin and soft tissue into visible folds. It can happen to anyone, regardless of body weight, and it’s often more noticeable during conversation than at rest because of the specific muscles involved in moving your mouth and jaw.
The Muscle That Bunches When You Speak
The biggest contributor is a broad, flat muscle called the platysma that stretches from your collarbone up across your neck and attaches to the lower part of your face. Unlike deeper muscles, the platysma sits just beneath the skin and is firmly stuck to it. When it contracts during speech, smiling, or any expressive facial movement, it shortens and physically bunches up, a phenomenon physicists call “buckling.” Think of pushing the ends of a sheet of paper together: it folds and ripples in the middle. That’s essentially what happens under your chin when the platysma fires.
The submandibular portion of this muscle (the part right under your jaw) moves skin forward and upward during contraction, temporarily increasing the diameter of your neck. So while you’re talking, especially if you’re animated or smiling broadly, the muscle is actively pushing soft tissue outward. The moment you stop and relax, the bunching often disappears or at least becomes less obvious.
Jaw Structure Plays a Bigger Role Than You’d Think
Your bone structure determines how much “shelf” exists to support the soft tissue under your chin. A jaw that sits slightly further back than average, sometimes called a receding chin, means there’s less bony projection to keep the skin taut. When you open your mouth to speak, the soft tissue has even less support, and gravity pulls it downward into a visible fold. You don’t need a dramatically small jaw for this effect. Even a mildly recessed chin can create noticeable submental fullness during movement that isn’t visible at rest or in photos taken from the front.
This is why some people notice the double chin only in certain angles or during specific activities like talking or looking down. The tissue is loosely draped over a relatively short platform of bone, and any jaw movement shifts it enough to become visible.
Muscles Under the Jaw Can Add Bulk
Beneath the platysma, a pair of muscles called the digastric muscles run from behind your ear to the underside of your chin. Their job is to help open your mouth, which means they’re actively working every time you speak. In some people, the front portions of these muscles are naturally larger, creating a sausage-shaped fullness under the skin that becomes more prominent when the neck is flexed or the jaw drops open during conversation.
When you tilt your chin up and extend your neck, the digastric muscles stretch and narrow, and the submental bulge improves. When you look down or open your mouth to talk, those muscles contract and thicken, doing the opposite. This is why the double chin can seem to come and go depending on your head position and whether you’re mid-sentence.
Fat, Skin Laxity, and Genetics
Not all of the fullness is muscular. A pocket of fat sits in the submental area in virtually everyone, and its size is influenced by a combination of genetics, aging, and overall body composition. Some people are genetically predisposed to store more fat under the chin regardless of their weight. You might be lean everywhere else and still carry noticeable fullness in this one spot.
Age compounds the issue. As skin loses elasticity over time, it drapes more loosely over the underlying fat and muscle. A younger person with firm skin might have the same amount of submental fat as an older person but show far less of it during speech because their skin snaps back into place more quickly. Once the skin starts to loosen, every contraction of the platysma and every drop of the jaw reveals more of what’s underneath.
Can Exercises Fix It?
Jaw and facial exercise devices are widely marketed for double chin reduction, but the clinical evidence is not encouraging. A review of the scientific literature found no strong data supporting the idea that jaw exercises reduce submental fat, enhance the jawline, or tighten facial skin. The chewing muscles these devices target don’t connect to the fat pad under your chin, so strengthening them doesn’t address the actual problem. One controlled study comparing facial exercise groups to a control group found no significant difference in wrinkles or sagging between the two.
That said, being aware of your head posture can make a real difference in the moment. Keeping your chin slightly lifted and your neck elongated during conversation reduces the bunching effect by putting the platysma and digastric muscles under gentle tension, which keeps them from folding the overlying skin.
Treatment Options That Work
If the double chin bothers you beyond what posture adjustments can manage, two main categories of treatment exist: injectable fat reduction and liposuction.
Injectable treatments use a synthetic version of a molecule your body already produces to break down dietary fat. The substance is injected directly into the submental fat pad over a series of sessions. Results are gradual, and multiple treatments are typically needed. Patient satisfaction, however, is mixed. An analysis of over 1,300 patient reviews found that only about 55% of injectable treatment reviews were positive.
Submental liposuction has been the standard approach since 1990 and consistently shows higher satisfaction. In the same analysis, 83% of liposuction reviews were positive, and the most common emotion expressed in those reviews was joy. For cases where enlarged digastric muscles are contributing to the fullness, surgeons can reduce the muscle bulk through the same small incision used for fat removal.
Cryolipolysis, which freezes and destroys fat cells through a device applied to the skin, reduces fat by roughly 25% per session in the treated area. Most people need only one or two sessions for the submental area, making it a middle ground between injectables and surgery in terms of both invasiveness and results.
Why It’s Worse on Camera
If you first noticed this issue during video calls or while watching yourself talk in a recording, you’re not imagining things. Cameras positioned at or below eye level, which is the default for laptops and phones propped on a desk, shoot upward into the underside of your jaw. This angle compresses the neck visually and catches every bit of platysma bunching and digastric thickening that occurs during speech. Raising your camera to slightly above eye level and angling it downward can dramatically reduce the appearance of submental fullness without changing anything about your anatomy.