A double chin usually comes from fat under the chin, loose skin, or an enlarged salivary gland under the jaw — often more than one at once. Each has its own treatment: a fat-dissolving injection (deoxycholic acid) or Linear Z focused ultrasound for fat, skin tightening with XERF or Sofwave for loose skin, and salivary gland Botox for an enlarged gland. The causes look alike in photos and in the mirror, so which applies is decided at an in-person assessment. COCO Clinic in Seoul offers all three routes without surgery.
Short Answer: Match the Treatment to the Cause
The better option depends on what is causing the fullness under your chin. Skin tightening suits loose skin, salivary gland Botox suits an enlarged gland, and fat is treated with a fat-dissolving injection or Linear Z rather than Botox. Only an in-person assessment can reliably tell these apart.
Salivary gland Botox is botulinum toxin injected into an enlarged salivary gland. It quietens the nerve signal that drives saliva production, so the gland gradually loses volume. Skin tightening works in the skin itself: Sofwave, for example, heats the dermis about 1.5 mm below the surface rather than the deeper SMAS layer.
COCO Clinic's published material notes that a jaw that stays wide after masseter Botox may reflect an enlarged salivary gland rather than muscle. That is a good reason to identify the cause before choosing a treatment.
- If the fullness seems to be mostly loose skin, skin tightening may be worth discussing with a clinician.
- If it may be an enlarged gland, salivary gland Botox may be worth discussing with a clinician.
- If it is mostly fat, a fat-dissolving injection or Linear Z is the route to discuss; Botox does not reduce fat.
The Three Common Causes: Fat, Loose Skin, and an Enlarged Salivary Gland
Three contributors are common, and each has its own definition. Submental fat is a layer of fat under the chin. Skin laxity is reduced tightness of the skin and its supporting tissue. An enlarged submandibular salivary gland is a gland near the jaw that has grown larger than expected.
These causes can overlap, so a single double chin may involve more than one. This is why a photo or a mirror check rarely settles the question.
COCO Clinic treats all three without surgery: skin tightening for loose skin, salivary gland Botox for an enlarged gland, and a fat-dissolving injection or Linear Z for fat. When more than one cause is involved, treatments can be combined, and the order is planned at the consultation. Liposuction and other surgery are outside what the clinic offers.
Clues You Can Notice at Home, and Why They Are Not a Diagnosis
Some observations are useful to bring to the clinic, but none of them is a test. Treat these as questions rather than answers:
- Does the fullness feel firm or soft?
- Does it sit toward the back of the jaw or directly under the chin?
- Does it persist when your body weight is lower?
- Did it stay the same after jawline-slimming Botox or a lifting treatment?
A clinician, not a photo comparison, should decide what is driving the shape. At COCO Clinic that starts with feeling the area by hand.
COCO Clinic describes its consultation as follows. A professional consultant provides a detailed one-on-one consultation, and the doctor may also conduct a brief assessment before the procedure. The clinic's part is to look at the skin and facial structure in person, and that is a different thing from a diagnosis made at home. Nobody should pick a treatment from photos or home checks alone.
What Skin Tightening Can and Cannot Address
Clinics usually call XERF and Sofwave "lifting" treatments. Under the chin, what they do is tighten loose skin:
- XERF heats the dermis broadly with radiofrequency, so the skin tightens a little straight away and firms further over 2–3 months as new collagen builds.
- Sofwave heats a single layer, the dermis at 1.5 mm, with seven parallel ultrasound beams. It targets the dermis rather than the SMAS.
Both work on the skin itself, not on the volume of a gland. That is why skin tightening fits loose skin rather than an enlarged gland. For a closer look, see How Does Radiofrequency Skin Tightening Work.
For timing, COCO Clinic's guidance is that for an important date, one to two months ahead is the usual reference point for lifting, since most treatments peak while collagen builds.
At COCO Clinic, skin tightening is offered for loose skin, not as a way to shrink a gland.
Treating Fat Under the Chin: Fat-Dissolving Injection and Linear Z
When the fullness is mainly fat, COCO Clinic uses one of two non-surgical routes, or both:
- A fat-dissolving injection uses deoxycholic acid (DCA), the same active ingredient as Kybella in the US. It is a prescription medicine approved in Korea for fat under the chin. It breaks down the membrane of fat cells, and cells that are destroyed do not come back, though the remaining ones can still grow with weight gain. It is usually done in 3–5 sessions, 4–6 weeks apart, and the change builds over several weeks to a few months.
- Linear Z is a focused-ultrasound (HIFU) lifting device. At its deeper 4.5 mm setting it tightens the support layer under the skin and can trim some fat along with it, which suits a heavier jawline and double chin.
The two do different jobs. The injection removes fat cells, so it suits a pocket of fat under the chin, but it brings noticeable swelling for several days to 1–2 weeks. Linear Z has almost no downtime and works on contour and firmness as well as fat.
When fat and loose skin are both involved, the fat is usually reduced first and the skin tightened afterwards. If both are done on the same day, the energy treatment goes first and the injection second. After the last fat injection, skin tightening on the same area waits two to four weeks.
What Salivary Gland Botox Does, and How Quickly It Works
Salivary gland Botox is botulinum toxin injected into an enlarged salivary gland. Under the chin, the gland involved is the submandibular gland, tucked under the lower corner of the jawbone; the parotid gland, in front of and below the ear, affects the width of the jaw instead. With less signal to secrete, the gland gradually loses volume. This differs from masseter Botox, which acts on the chewing muscle.
At COCO Clinic, the usual timeline is:
- Change begins gradually at 1–2 weeks.
- It is clearest at 4–6 weeks.
- It typically lasts 4–6 months, and sessions are usually spaced 6–12 months apart.
COCO Clinic lists salivary gland Botox among its Botox services, alongside wrinkle and jaw-muscle treatments. Before treating, the doctor checks whether the gland, the muscle or the skin is driving the shape, and does not recommend the treatment when the gland is not a significant part of the picture.
Skin Tightening, Fat Treatment and Salivary Gland Botox at a Glance
The table below compares what each route does. It is not a ranking: each one treats a different cause.
Skin tightening works in the skin, fat treatment reduces the fat under the chin, and salivary gland Botox shrinks an enlarged gland. An in-person assessment decides which fits.
| Question to ask | Skin tightening (XERF, Sofwave) | Fat treatment (fat-dissolving injection, Linear Z) | Salivary gland Botox |
|---|---|---|---|
| What it works on | The skin (Sofwave: dermis at 1.5 mm; XERF: dermis and the layer beneath) | Fat under the chin | An enlarged submandibular gland |
| When change shows | Slight tightening at once; builds over about 2–3 months | Injection: over several weeks to a few months, across 3–5 sessions; Linear Z: over 2–3 months | Begins at 1–2 weeks; clearest at 4–6 weeks |
| How long it lasts | XERF usually about 6–12 months; Sofwave is reviewed by how the skin looks | Fat cells removed by the injection do not come back | About 4–6 months |
| Downtime | Almost none; daily life the same day | Injection: swelling for several days to 1–2 weeks; Linear Z: almost none | None; back to your day straight away |
| Main side effects | Temporary redness, warmth or mild swelling | Swelling, bruising, tenderness; rarely a temporarily uneven smile | Dry mouth if the dose is too high; rarely a temporarily uneven smile |
COCO Clinic's recommendation depends on an in-person assessment. Because it offers all three routes, it can suggest one, or combine them when more than one cause is involved; that does not mean every patient is offered all three.
Side Effects and Limits of Each Route
Skin tightening. Temporary redness, warmth or mild swelling that settles within hours to a few days. Daily life is fine the same day with either device. After XERF, make-up is fine the same day; after Sofwave, face washing, skincare, make-up and sunscreen start the next day.
Fat-dissolving injection. Swelling is considerable and can last several days to 1–2 weeks, with bruising, tenderness, a firm feeling or numbness in the area. Rarely, irritation of the nerve along the jaw causes a temporarily uneven smile, which is why precise placement matters. It is not done during pregnancy or breastfeeding, or where the area is infected or inflamed. Tell the clinic about any swallowing difficulty, bleeding tendency or blood thinners.
Linear Z. Temporary redness, prickling or mild swelling; occasionally tenderness or fine bruising.
Salivary gland Botox. If the dose is too high, the mouth can feel dry or food harder to swallow for a while; drinking water more often usually helps. A temporarily uneven smile is possible if the toxin spreads toward nerve branches near the gland. It is not done during pregnancy or breastfeeding, with a neuromuscular condition such as myasthenia gravis, or when the area is inflamed or infected. Tell the clinic if you take aminoglycoside antibiotics.
Results vary between individuals. When more than one cause is involved, one treatment alone may leave part of the fullness, which is why the cause is checked first. Surgery, including liposuction, is outside COCO Clinic's scope.
Planning From Abroad: Timing, Assessment, and Seoul Logistics
Each route runs on a different clock, which matters if you are visiting Seoul. Salivary gland Botox takes under 5 minutes and you can go straight back to your day, but the change is clearest at 4–6 weeks, so you will most likely be home before you see it. Skin tightening and Linear Z build over 2–3 months; for an important date, one to two months ahead is the usual reference point. The fat-dissolving injection is usually done in 3–5 sessions, 4–6 weeks apart, with swelling in the first days, so it suits a longer stay or repeat visits better than a single short trip.
Before booking flights, ask the clinic how assessment, treatment and follow-up would work for you.
COCO Clinic is in Seoul, and its medical director is Dr. Jay. If you are weighing skin tightening, fat treatment and salivary gland Botox, you can ask the clinic which assessment fits your situation.
Results vary between individuals.
Frequently Asked Questions
How can I tell whether my double chin is fat, loose skin, or a salivary gland?
These causes can look alike and often overlap, so only an in-person assessment can separate them. Home observations are questions to bring to a consultation, not diagnostic tests.
Should I try lifting or salivary gland Botox first?
Neither comes first by default: the first step is finding the cause. Lifting treatments such as XERF and Sofwave tighten loose skin, salivary gland Botox shrinks an enlarged gland, and fat is treated with a fat-dissolving injection or Linear Z. When more than one cause is involved, the order is planned after the assessment; with fat and loose skin together, the fat is usually reduced first.
Can a double chin from fat be treated without surgery?
Yes. A fat-dissolving injection with deoxycholic acid breaks down fat cells under the chin over 3–5 sessions, 4–6 weeks apart, and the cells it removes do not come back. Linear Z focused ultrasound can tighten the area and trim some fat with almost no downtime. Expect swelling for several days to 1–2 weeks after each injection session.
How long does salivary gland Botox take to work and how long does it last?
Change begins at 1–2 weeks, is clearest at 4–6 weeks and typically lasts 4–6 months. Results vary between individuals.
What are the main risks of salivary gland Botox?
If the dose is too high, the mouth can feel dry or food harder to swallow for a while. A temporarily uneven smile is possible if the toxin spreads toward nearby nerve branches, which is why injection depth and placement matter. It is not done during pregnancy or breastfeeding or with a neuromuscular condition such as myasthenia gravis.
What if salivary gland Botox does not change my double chin?
That usually means the gland was not the main cause. Fat or loose skin may be contributing more, and those are treated with a fat-dissolving injection, Linear Z or skin tightening. This is why the cause is checked before any treatment.
References
- [1] Masseter Botox but No Change? It May Be Your Salivary Glands — COCO Clinic