A double chin in Busan Seomyeon, and which of the four causes is yours.

This is the area where a treatment can work exactly as intended and change nothing visible, because the thing being treated was not the thing causing the appearance. Sorting the components first is worth more than any single treatment.

Cause one — submental fat

A discrete fat pad beneath the chin, often present in people who are otherwise slim and frequently familial. It sits above the platysma muscle and does not respond proportionally to weight loss, which is why patients describe losing ten kilograms without changing their profile. It reads as a soft fullness rather than a fold, and it is the component people assume is the whole problem.

Cause two — skin and platysma laxity

Loss of firmness in the skin and underlying muscle sheet, which produces a softened jaw contour without any excess volume. The distinguishing test is lying down: if the contour improves markedly when you are horizontal, gravity and laxity are the drivers rather than fat. This is what energy lifting addresses, and it responds well up to a point beyond which surgery does more.

Cause three — a recessed or short chin

The cause patients least expect and the one that changes the profile most for the least intervention. A chin that sits behind the ideal projection line shortens the distance between chin and neck, which reads as a double chin even with no excess fat and normal skin. Chin filler extends that line and sharpens the entire lower face — often a more dramatic profile change than treating the fat would produce.

Cause four — posture and the cervical angle

Forward head posture from screen use shortens the neck line and softens the jaw contour, and no treatment corrects it. This is worth knowing because a proportion of what people photograph as a double chin appears only in their habitual head position. Photographs taken with the chin level and the head back frequently look entirely different — which is a reason to assess in profile with corrected posture rather than from a phone photograph.

How is the combination assessed?

Three checks that take under a minute. Pinching beneath the chin to estimate fat volume against skin thickness. Comparing the contour upright and lying down to separate laxity from fat. And assessing chin projection against the lower lip in profile, which identifies the recessed chin component. Most patients have two of the four, and the ratio decides the plan — see how a consultation works.

What treats which?

Energy lifting and InMode for laxity and moderate fat, since RF addresses both to a degree. Chin filler for projection. Jaw botox where a heavy masseter is widening the lower face and contributing to the impression. Threads where laxity is moderate and a lift is wanted with definition. Significant isolated fat is the one component where non-surgical options are weakest.

Why do so many patients treat the wrong component?

Because the visible appearance points at the wrong place. A shadow under the chin reads as fat to almost everyone who sees it in a photograph, so that is what people search for and what they ask to have removed. When the actual driver is chin projection, removing fat that was never the problem produces a slimmer version of the same profile — the patient loses the fullness and keeps the shadow, and reasonably concludes the treatment did not work. The examination exists precisely because the appearance is not diagnostic here.

How does the neck fit into this?

More than patients expect, and it is frequently left out of the plan entirely. The platysma runs from the chest across the jawline, and as it loosens it pulls the lower face downward as well as producing vertical neck bands. Treating the jaw while ignoring the neck leaves a defined jawline sitting above a slack neck, which reads oddly. Where laxity is the dominant cause, lifting is applied across both regions rather than to the jaw alone — and botox into prominent platysmal bands is sometimes part of that.

What order should they be treated in?

Projection first where a recessed chin is a component, because it changes how much of the rest is needed. Volume and laxity next. Masseter last, since jaw botox takes four to eight weeks to show and its contribution is easier to judge once the profile has been addressed. Treating everything simultaneously makes it impossible to attribute the result — see combining treatments.

What are the honest limits?

Substantial submental fat with significant skin laxity is where non-surgical treatment underdelivers, and saying so is more useful than a package that will disappoint. Where skin has lost most of its elastic recoil, tightening produces a modest improvement rather than a jawline. Patients in that category are better served by an honest referral conversation than by three sessions of something that was never going to reach it.

How much difference is realistic?

For a recessed chin treated with filler, considerable — this is one of the largest profile changes available from a small volume. For laxity treated with energy, gradual and worthwhile over three months. For moderate fat, modest. Photographs in profile under fixed lighting are the only reliable way to judge, since this is an area where memory and mirrors are both unreliable.