Seoul
Chief MD, Gangnam
Duk-ha Kim
The trust our patients have placed in this clinic was built on conviction and principle. We intend to hold to both, unchanged, through the next hundred years.
Botulinum toxin treatment guide
Mouth Corner Toxin
Mouth corner toxin is an injection of botulinum toxin type A into the depressor anguli oris, the muscle that pulls the corner of the mouth downward. None of the records cited on this page lists that muscle or the oral commissure as an indication — not the U.S. labels for BOTOX Cosmetic or XEOMIN, not the Korean MFDS records for BOTOX injection or XEOMIN injection — so the use is off-label in both jurisdictions. Two controlled trials have looked at injecting the muscle. Off-label does not mean illegal; it means no regulator has assessed data for this site, so there is no approved dose, no approved injection map and no label-level account of what can go wrong here.
- Target muscle
- Depressor anguli oris (DAO) — pulls the corner of the mouth downward
- Regulatory status
- Off-label on every record cited here, U.S. and Korean alike
- Evidence base
- Two controlled trials on DAO injection; the 2023 one ran 20 participants to 12 weeks
- Labelling
- Boxed warning: distant spread of toxin effect. Unit numbers carry no meaning across products
A menu item named after the mouth corner — where does the needle actually go?
The name describes a place on your face, not an injection site, and those are not the same thing. The muscle this menu points at is the depressor anguli oris, usually shortened to DAO: a small triangular muscle that runs up from the lower jaw and inserts at the corner of the mouth. It is the muscle the two controlled trials cited on this page injected. Several muscles act on that corner, so the corner itself is an area rather than a target, and a menu name says nothing about which of them a clinician intends to treat or how many points they plan to use. Before booking, get the muscle named, the number of points per side named, and whether the plan covers one side or both — all three vary, and none of them is implied by the words on the menu.
Sources: Zhang et al., Plast Reconstr Surg 2026 — two-stage double-blind RCT on DAO injectionMoradi et al., Dermatol Surg 2023 — placebo-controlled DAO study
What is the depressor anguli oris doing when you are not thinking about it?
It pulls the corner of the mouth down and slightly outward, and it does so as part of ordinary movement rather than only in an expression you choose. The DAO belongs to the muscles of facial expression, not to the chewing group: it works while you talk, eat, drink and react, and it is one contributor among the perioral muscles that shape the lower face. That matters for reading this menu honestly. The stated mechanism is to weaken a muscle that is doing a job, so the question in a consultation is not only what will look different but how much of the movement at that corner the clinician intends to take away, and what remains to balance it. The two trials cited measured where the corner and the lip sat, which is a direct acknowledgement that this injection moves a moving part.
Sources: Zhang et al., Plast Reconstr Surg 2026 — two-stage double-blind RCT on DAO injectionMoradi et al., Dermatol Surg 2023 — placebo-controlled DAO study
Does any of these labels list the mouth corner as an indication?
No — and the absence is literal rather than a matter of interpretation. On the U.S. label for BOTOX Cosmetic the adult indications are glabellar lines, lateral canthal lines, forehead lines and platysma bands, and the strings depressor anguli oris and oral commissure do not appear anywhere in it. The U.S. label for XEOMIN covers the same three upper-face areas plus chronic sialorrhea; the only mouth-related item there concerns saliva, not the muscle that pulls the corner down. In Korea the MFDS record for BOTOX injection lists eight indications, of which glabellar lines is the only cosmetic one, and neither the mouth corner nor the DAO is among them; the MFDS record for XEOMIN injection lists three upper-face wrinkle indications and nothing below the eyes. The U.S. labelling adds, under Limitations of Use, that safety and effectiveness for uses other than those described have not been established. This page checked U.S. and Korean records only and makes no claim about any other country.
Sources: FDA label — BOTOX CosmeticFDA label — XEOMIN (incobotulinumtoxinA)MFDS drug product record — BOTOX injection (Korea)MFDS drug product record — XEOMIN injection (Korea)
Off-label: what does it change for you, and what does it not mean?
It does not mean illegal. A licensed clinician may prescribe a licensed drug outside its approved indications, and doing so is a recognised part of practice. What it changes is everything downstream of the regulator: with no assessed submission for this muscle there is no approved dose, no approved injection map, no defined patient group and no label section listing what happens at this site. Published trials exist, and the next section sets out exactly what they cover, but a journal article is not a licence — it is not reviewed the same way, it does not create an indication, and it does not transfer to a product it did not test. Practically, the judgement moves to the clinician and the explanation moves to you, which is why an off-label plan should be said out loud, written down, and agreed rather than assumed from a price list.
Sources: FDA label — BOTOX CosmeticZhang et al., Plast Reconstr Surg 2026 — two-stage double-blind RCT on DAO injection
What has actually been studied here, and how far does it stretch?
Two controlled studies, both small enough that the size belongs in the conversation. Moradi and colleagues published a placebo-controlled study in Dermatologic Surgery in 2023: 20 participants, 10 treated and 10 on placebo, 1.5 Units per point at three points, followed to 12 weeks. Zhang and colleagues published a two-stage double-blind randomised controlled trial of DAO injection in Plastic and Reconstructive Surgery in 2026; injection into the lower part of the DAO outperformed the comparison, combining the DAO with a further injection point outperformed the DAO alone, the reported lip asymmetry measure (DSL) differed by less than 1 mm, and the authors report no severe adverse events. Read all of that at its own scale. This page does not quote a participant count or a follow-up length for the 2026 trial, so take its design — double-blind, randomised, controlled — and nothing numerical beyond what is stated here. A sub-millimetre difference is a measurement, not a verdict that two approaches look alike. And no severe adverse events in studies of this size tells you about these participants over these weeks; it cannot establish how often uncommon problems occur.
Sources: Moradi et al., Dermatol Surg 2023 — placebo-controlled DAO studyZhang et al., Plast Reconstr Surg 2026 — two-stage double-blind RCT on DAO injection
How long does the effect last?
No duration figure appears in the labels cited on this page, because neither product’s approved indications include this site, so there is nothing there to quote for the DAO. The only timeframe actually observed comes from the trials: Moradi and colleagues followed 20 participants to 12 weeks, and the 2026 trial by Zhang and colleagues does not state a follow-up length on the record available here. Twelve weeks of observation in 20 participants describes how long those participants were watched, not a stated duration of effect, and neither trial reports what happened to the treated corner once its observation window closed. Because this use sits outside the approved indications, there is also no approved re-treatment interval to fall back on — that decision is made by the treating clinician case by case. Ask which study any duration figure quoted to you comes from, and ask the clinician what they have personally observed about how long the change holds and when they would reassess before considering another injection.
Sources: Moradi et al., Dermatol Surg 2023 — placebo-controlled DAO studyZhang et al., Plast Reconstr Surg 2026 — two-stage double-blind RCT on DAO injection
Why does the boxed warning weigh more heavily around the mouth?
The U.S. labelling for these products carries a boxed warning headed WARNING: DISTANT SPREAD OF TOXIN EFFECT. Effects may occur away from the injection site, and the labelling names swallowing and breathing difficulties that can be life-threatening, reported hours to weeks after injection. The reason to read it carefully at this site is proximity: the structures immediately around the corner of the mouth are the ones that keep the lips sealed, hold food and liquid in, and start a swallow. A spread event here is therefore not an abstract possibility on a distant part of the label. The trials cited report no severe adverse events, but that finding sits inside small studies and does not replace a warning written from post-marketing reports. Agree before the injection that any swallowing or breathing difficulty is treated as urgent and contacted about immediately, rather than watched for a few days.
Sources: FDA label — BOTOX CosmeticFDA label — XEOMIN (incobotulinumtoxinA)Zhang et al., Plast Reconstr Surg 2026 — two-stage double-blind RCT on DAO injection
Could it change how your face moves, or how you speak?
A change in how the lower face moves is the intended mechanism, not an unexpected complication: the injection works by weakening a muscle that moves the corner of your mouth. What is undefined is the amount, because no approved dose or injection map exists for this site, and unevenness between the two sides is the thing to watch — the 2026 trial reported a lip asymmetry measure (DSL) precisely because the position of the corner and lip is what this injection shifts. If your work depends on precise speech or on singing, raise it explicitly at the consultation and ask what the clinician has observed and how they would handle it. Keep this separate from the boxed warning: swallowing and breathing difficulty is a labelled risk of toxin spread.
Sources: Zhang et al., Plast Reconstr Surg 2026 — two-stage double-blind RCT on DAO injectionFDA label — BOTOX Cosmetic
When must the injection not go ahead, and what has to be disclosed?
Two contraindications are stated on the U.S. labelling: known hypersensitivity to any botulinum toxin preparation or to any component of the formulation, and infection at the proposed injection site. Beyond those absolutes, the labelling calls for caution where a neuromuscular disorder is present — myasthenia gravis, Lambert-Eaton syndrome, amyotrophic lateral sclerosis are the named examples — and in anyone who already has difficulty swallowing or breathing. Disclose pregnancy and breastfeeding, every current medicine, and previous toxin injections with their dates and product names. Around the mouth, add anything structural: earlier surgery or injectable material near the lips or chin, dental work that changed how the lower face sits, any history of facial nerve weakness, and asymmetry you already have. Photograph your own resting and smiling face beforehand; it is the only baseline that is genuinely yours. Because this site is off-label, none of these cautions is offset by a dataset a regulator has examined for the DAO.
Sources: FDA label — BOTOX CosmeticFDA label — XEOMIN (incobotulinumtoxinA)
Can two quotes be compared by the number of Units in them?
They cannot. A potency Unit is defined by each manufacturer through its own assay and is meaningful only for that preparation. The BOTOX Cosmetic label states that its Units cannot be compared to nor converted into Units of any other botulinum toxin product, and the XEOMIN label carries the same restriction, so there is no factor to convert with and no reading in which the same figure from two products describes the same dose. The 1.5 Units per point in the 2023 placebo-controlled study is a parameter of that study and the product it used; it is a description of what was tested, not a dosing rule to carry to a different vial or a different face. The product name is also what tells you which regulatory record applies, so it is the first thing to ask for and the one thing a quote cannot be read without.
Sources: FDA label — BOTOX CosmeticFDA label — XEOMIN (incobotulinumtoxinA)Moradi et al., Dermatol Surg 2023 — placebo-controlled DAO study
What should be settled in the consultation before you book?
Ask the clinician to state, in words, that this is an off-label use rather than an approved indication — if that sentence is difficult to obtain, you have learned something. Then get the specifics: the product name on the vial, the dose in that product’s own Units, the number of points per side, one side or both, which muscle each point is aimed at, what the clinician expects to change and on what basis, and what they would do if the two sides settle unevenly. Agree a review point and agree, in advance, the list of symptoms that mean you call rather than wait: difficulty with swallowing or breathing first, then drooling, a lip or corner that behaves differently on one side, or trouble sealing the lips. The needle enters muscle, so a short sting on entry and soreness or a bruise at each point afterwards are possible, and the treating clinic should give you its own aftercare instructions. If you are visiting for a short stay, say your departure date at the consultation and settle who reviews you and how you reach them once you are home.
Sources: FDA label — BOTOX CosmeticMoradi et al., Dermatol Surg 2023 — placebo-controlled DAO study
What does each record actually list, and where does the mouth corner sit?
Approval is granted per product and per named use, and a study is not an approval. This table sets out only what the cited records list and what the cited trials examined, so the gap between the two is visible. It does not compare how well products work and it ranks nothing.
| Record or study | What it lists or examined | Mouth corner / DAO | Nearest mouth-area item |
|---|---|---|---|
| United States — BOTOX Cosmetic (FDA label) | Glabellar lines, lateral canthal lines, forehead lines, platysma bands | Not listed — depressor anguli oris and oral commissure appear nowhere in the label | None |
| United States — XEOMIN (FDA label) | Glabellar lines, lateral canthal lines, forehead lines, chronic sialorrhea | Not listed | Chronic sialorrhea — about saliva, not the muscle that pulls the corner down |
| Korea — BOTOX injection (MFDS record) | Eight indications; glabellar lines is the only cosmetic one | Not listed | None |
| Korea — XEOMIN injection (MFDS record) | Three upper-face wrinkle indications | Not listed | None |
| Moradi et al. 2023 (Dermatol Surg) | Placebo-controlled study: 20 participants, 10 treated and 10 placebo, 1.5 Units per point at three points, 12 weeks of follow-up | Examined — but a study is not a licence | Not applicable |
| Zhang et al. 2026 (Plast Reconstr Surg) | Two-stage double-blind randomised controlled trial; lower-DAO injection outperformed the comparison, DAO plus a further point outperformed DAO alone, reported lip asymmetry (DSL) differed by under 1 mm, no severe adverse events reported | Examined — but a study is not a licence | Not applicable |
Off-label use means use outside the licensed indication. It is not illegal, but it means no regulator has assessed data for that use, so the decision rests on clinical judgement and should be explained to you and recorded. Participant numbers and follow-up length for the 2026 trial are not quoted on this page. Unit figures belong to the product that was tested and do not convert to another product. The records checked here are U.S. and Korean; nothing on this page describes the position in any other country.
Sources: FDA label — BOTOX CosmeticFDA label — XEOMIN (incobotulinumtoxinA)MFDS drug product record — BOTOX injection (Korea)MFDS drug product record — XEOMIN injection (Korea)Moradi et al., Dermatol Surg 2023 — placebo-controlled DAO studyZhang et al., Plast Reconstr Surg 2026 — two-stage double-blind RCT on DAO injection
Medical care at Abijou
Care is provided by the medical team at the branch you select. These clinicians lead the three branches linked from this guide; confirm the doctor assigned to your visit with that branch.
Chief MD, Myeongdong
Cheol-su Yoon
I want to be thinking about how the patient feels right up to the last moment of the procedure.
Chief MD, Hongdae
Jae-wook Kim
I will give my best with the attentiveness to catch even the smallest change.
Listed branch medical team — not a medical-review byline for this article.
Frequently asked questions
What is mouth corner toxin?
It is an injection of botulinum toxin type A into the depressor anguli oris, the muscle running from the lower jaw to the corner of the mouth that pulls that corner downward. On every record cited here the use is off-label: neither the U.S. labels for BOTOX Cosmetic and XEOMIN nor the Korean MFDS records for BOTOX injection and XEOMIN injection lists the depressor anguli oris or the oral commissure.
Is something lifted, or is something filled in?
Neither. Nothing is repositioned, no material is placed and no skin is removed — the injection weakens one muscle so that its downward pull on the corner is reduced. That is why the result depends on how much of the movement at your own mouth corner comes from that particular muscle, which is an in-person assessment and not something a menu name can settle.
How does the drug change a muscle?
Botulinum toxin type A blocks the release of acetylcholine at the neuromuscular junction, so the injected part of the muscle contracts less until the nerve terminals recover and the effect recedes. The drug behaves the same way wherever the needle goes; what differs at the mouth corner is the paperwork, not the pharmacology — no regulator on the records cited here has assessed data for this site.
How is this different from toxin for frown lines or forehead lines?
The review status differs, and so does what the muscle is for. Glabellar, lateral canthal and forehead lines are listed indications on the U.S. labels for BOTOX Cosmetic and XEOMIN, meaning a regulator examined data for them, and Korea lists glabellar lines and the upper-face areas in narrower form. Mouth corner injection appears on none of those. The functional stake is different too: the upper-face targets crease skin, while the depressor anguli oris sits among the muscles you use while talking and eating.
A clinic offered filler at the mouth corner instead — how do the two compare?
They are different interventions, and this page can only speak for one of them. Toxin reduces a muscle’s pull; a filler places material. Every source cited here is a botulinum toxin record or a toxin trial, so nothing on this page supports or rules out a filler approach at this site, and no head-to-head result exists here. If a clinic proposes one over the other, ask which structure each is meant to act on, what evidence they are relying on for this specific site, and what the plan is if the result is uneven.
Two clinics quoted different products and different Unit numbers — how do I compare them?
Not by the Unit numbers. Potency Units come from each manufacturer’s own assay: the BOTOX Cosmetic label states its Units cannot be compared to nor converted into Units of any other botulinum toxin product, and the XEOMIN label carries the same restriction. The 1.5 Units per point in the 2023 placebo-controlled study describes that study and its product; it is not a conversion key. Ask for the product name, then the dose in that product’s own Units and the points per side — a quote without all three is not comparable to anything.
Does it hurt, and will it bruise?
The needle goes into muscle, so expect a short sting as it enters and possibly soreness or a bruise at each point afterwards. No pain score or recovery timetable can be quoted from the sources here, because the labels do not cover this site. Bruising around the mouth is hard to hide, so if you have something in the diary, ask the clinic how they would plan around it and what they advise for the rest of the day.
When would anything show, and how long does it last?
No duration can be stated from these sources. The cited labels do not cover this site, so there is no approved figure to quote, and the only timeframe on this page is the follow-up length of the 2023 study — 12 weeks, which is how long those 20 participants were observed rather than how long an effect lasts. If a clinic quotes you a number of months, ask which study and which product it comes from.
How many sessions, and how soon could a second one follow?
These sources set no interval and no session count. There is no approved schedule for this site, and neither trial cited here is quoted as establishing one, so repeat timing is a clinical judgement made case by case. Bring the date and product name of any previous toxin injection so the clinician is not working blind, and ask what they would change at a second session if the first result came out uneven.
Who must not have this injection at all?
It is contraindicated in anyone with known hypersensitivity to a botulinum toxin preparation or to any component of the formulation, and where there is infection at the proposed injection site. The labelling also calls for caution in neuromuscular disorders such as myasthenia gravis, Lambert-Eaton syndrome and amyotrophic lateral sclerosis, and in people who already have difficulty swallowing or breathing. Pregnancy, breastfeeding, current medicines, previous toxin injections and any earlier surgery or injectable around the mouth must all be disclosed. Because this site is off-label, no dataset examined by a regulator for the DAO sits on the other side of those cautions.
Could it change my smile, or how I speak?
A change in how the lower face moves is the intended mechanism rather than a surprise — what is undefined is how much. The injection weakens a muscle that moves the corner of your mouth, so ask how much movement the clinician means to remove and what they do if the sides end up uneven; the 2026 trial reported a lip asymmetry measure (DSL) for that reason. Raise it directly at the consultation if you speak or sing for a living. Swallowing or breathing difficulty is a different matter, covered by the boxed warning, and is urgent.
Is it approved anywhere, and is off-label use allowed?
It is not an approved indication on any record cited here, in the United States or Korea, and off-label use is not illegal. BOTOX Cosmetic lists glabellar lines, lateral canthal lines, forehead lines and platysma bands; the U.S. XEOMIN label lists three upper-face areas plus chronic sialorrhea; the Korean record for BOTOX injection lists eight indications of which glabellar lines is the only cosmetic one; the Korean XEOMIN record lists three upper-face wrinkle indications. A licensed clinician may prescribe outside the label, but the U.S. labelling states that safety and effectiveness for uses other than those described have not been established, so the decision rests on clinical judgement and should be explained to you and written into your record.
What has to match before two quotes can be compared on price?
Line up what each quote contains before comparing the amounts: product name, dose in that product’s own Units, points per side, one side or both, whether a review visit or any adjustment is included, and whether it is a single session or a package. Units do not convert between products, so two quotes built on different products are not measuring the same thing even when the figures look close. A quote that names no product cannot be compared at all.
Who is a candidate, and does a short stay allow for it?
There is no approved patient group for this site, so suitability is an in-person judgement rather than something a photograph decides. What has to be assessed is how your mouth corner actually moves, how much of that movement comes from this muscle, and what asymmetry is already there — photograph your own resting and smiling face beforehand so you have a baseline. On a short trip, give your departure date at the consultation and agree who reviews you and how you reach them, because anything you notice about movement or asymmetry may only appear after you fly home.
How Abijou works
We started in Gangnam in 2006 and the network now runs 17 branches across Korea. The line we work to is skin transformation woven into everyday life — care you can keep up with, rather than one dramatic change.
- Across the 17 branches in Seoul, Gyeonggi, Incheon and Busan: over 1,000 medical professionals and more than 350 certified medical devices
- Authentic products only, in appropriate amounts — the treatment is fitted to the condition, not to a package
- Prices are quoted from each branch’s published price list as it stands
Contact and location
- Phone
- 1544-0377
Free Consultation
Booking happens at the branch
There is no inquiry form on this page. Once you have picked a branch above, open that branch’s site or the official reservation center and choose a time yourself.
- No deposit and no online prepayment — everything is paid at the visit
- Per-treatment prices are published for each branch on the official reservation center
- English, Japanese and Chinese are supported alongside Korean