Skip to main content
Botox Muscle Reduction
Back to treatments

Botox Muscle Reduction

Botox Muscle Reduction

A jawline that looks square because the chewing muscle has thickened. Without touching the bone, we reduce only the muscle volume — in about five minutes.

Duration

Under 5 min

Injection only

Pain

Low–moderate

Fine needle · topical

Downtime

Same day

Makeup same day

Price

₩90,000~

For 50 units · varies by product

All prices shown include VAT.

When muscle is the reason your jaw looks square

A wide-looking jawline generally comes from one of three things: bone, fat, or muscle. When it is the masseter — the chewing muscle — that has thickened and squared off the lower face, the contour can be refined by reducing muscle volume alone, without touching the bone structure.

Botox muscle reduction injects botulinum toxin into the masseter to temporarily lower its contractile activity. A muscle that is used less gradually decreases in volume, and the squared jawline settles into a gentler curve.

The injection itself takes five minutes and has no downtime, so you can go straight back to your day. The change, however, is not immediate — it emerges gradually over two to four weeks.

Type

Injection · botulinum toxin

Target

Masseter muscle

Onset

2-4 weeks

Duration

6-12 months

Cause

Why the masseter thickens

The masseter is a muscle, so repeated use thickens it much like any trained muscle. The more of the following overlap, the more it develops.

Grinding & clenching

Grinding during sleep or unconsciously clenching through the day loads the masseter continuously. Waking with a stiff jaw or tight temples is a common clue.

Chewy-food habits

Frequently eating gum, dried squid, or jerky repeatedly stimulates the chewing muscles. Chewing habitually on one side can also lead to left–right asymmetry.

Constitution & structure

With identical habits, development still varies with how readily one builds muscle and how the muscle attaches. Here it is especially important to check whether a bone factor is also present.

If the jawbone itself is wide, what Botox alone can change is limited. That is why identifying the cause comes first in consultation.

Mechanism

How it works

Neuromuscular blockade — turning down the signal

Botulinum toxin inhibits the release of acetylcholine at the neuromuscular junction, where nerve meets muscle. As the "contract" signal weakens, the masseter's activity level falls.

Disuse atrophy — less use, less bulk

Just as muscle shrinks when training stops, a less active masseter gradually loses volume. This is the stage that actually changes the jawline — and it is reversible: the cells do not disappear, they simply become smaller.

Onset and recovery — why it takes time

Signal blockade begins right after injection, but volume loss takes time — the change appears over 2-4 weeks and is most evident around 6-8 weeks. The nerve then recovers gradually, returning toward baseline over 6-12 months.

Key effects

1

A refined jawline

The angular lower face settles into a gentler curve, softening the overall impression.

2

Less muscle overactivity

Morning jaw stiffness and tension headaches around the temples from grinding or clenching often ease alongside.

3

Non-surgical, no pause

No incision, no general anesthesia — five minutes, then straight back to your day.

Treatment areas

Masseter — square jaw

The most common site. We palpate the muscle bulk that stands out when you clench, then distribute the injection within that area.

Temporalis — temples & headache

A chewing muscle that closes the jaw alongside the masseter. With heavy grinding it develops too, making the temples bulge and sometimes causing tension headaches. Treating the masseter alone can lead the temporalis to compensate, so we assess both together.

Trapezius — shoulder line

Treating the upper trapezius — the muscle that can make the neck look short — softens the shoulder line. It is a separate area from the masseter and can be combined after consultation.

Process

How the session runs

  1. 1

    Consultation & palpation

    With your teeth clenched, we palpate the thickness and extent of the masseter and check whether bone or fat factors are also involved.

  2. 2

    Dose & point planning

    We set the dose and injection points considering muscle mass, left–right asymmetry, skin elasticity, and cheek fat volume together.

  3. 3

    Injection

    Using a fine needle, the dose is distributed across several points within the masseter, at a depth and position that avoid the facial nerve and parotid gland. It finishes within five minutes.

  4. 4

    Follow-up & next plan

    After 2-4 weeks we review how the effect has developed, fine-tune if needed, and advise on the next session timing with tolerance risk in mind.

Recommended for

  • Those whose lower face looks square from a developed masseter
  • Those with a frequently stiff jaw from grinding or clenching
  • Those who want to refine facial contour without surgery
  • Those who want a short procedure with no downtime
  • Those who want to maintain their jawline with regular care

Aftercare & precautions

  • Do not touch or press the injection site for 4 hours. Also avoid sleeping face-down or massaging the area.
  • Avoid alcohol on the day of treatment and refrain from vigorous exercise for 24 hours.
  • Effects appear over 2-4 weeks and peak around 6-8 weeks — do not judge the result in the early days.
  • For the first 2-4 weeks you may feel stiffness or weaker chewing strength, which usually settles on its own.
  • To maintain results and prevent tolerance, we recommend spacing retreatment at least 6 months apart.
  • Treatment is not available during pregnancy or breastfeeding, or for those with neuromuscular disorders.

Frequently asked questions

Botulinum toxin is injected into the developed masseter (chewing) muscle to temporarily reduce its contractile activity. With less use, the muscle gradually decreases in size (disuse atrophy), so a squared jawline softens into a smoother contour. Unlike jaw-reduction surgery it does not change the bone itself, so it suits cases where muscle bulk — not bone structure — is the cause.

You will not see a change immediately after injection — the muscle needs time to shrink. Results appear gradually over 2-4 weeks, with maximum effect around 6-8 weeks, and last roughly 6-12 months depending on individual muscle mass and chewing habits. Retreating before the muscle fully recovers lets the reduction accumulate, so the effect tends to last longer with each repeated session.

The injection itself takes under 5 minutes and there is no downtime — you can return to daily life right away. Small needle marks or mild redness may remain briefly but usually settle within a few hours, and makeup is possible the same day. For 4 hours after injection, however, avoid rubbing or pressing the treated area.

It is uncommon but possible. Botulinum toxin is a protein, so repeated exposure can lead to neutralizing antibodies that reduce its effect. This is mainly associated with frequent retreatment at short intervals and excessive dosing. Keeping to the recommended interval (6 months or more) and using only the dose actually needed lowers that risk — which is why COCO Clinic does not recommend topping up while the previous effect is still present.

With an appropriate dose placed accurately, this is uncommon. However, as the masseter shrinks, the support beneath the overlying skin and fat also decreases — so in people who already have little cheek fat or reduced skin elasticity, an excessive dose can make the cheeks look hollow. For this reason we assess skin elasticity and fat volume alongside masseter development when setting the dose, and discuss combining with a lifting treatment when appropriate.

It is not needed for everyone — it depends on whether the temporalis has developed too. The temporalis closes the jaw together with the masseter, so heavy grinding thickens it as well, which can make the temples look convex or produce tension headaches starting there. Treating only the masseter can leave the temporalis compensating and the headache persisting, so we palpate the temples with your teeth clenched during consultation and decide together.

For 4 hours after injection, do not touch or press the treated area; avoid alcohol that day and vigorous exercise within 24 hours. For the first 2-4 weeks you may feel stiffness or reduced chewing strength, which usually settles on its own. Treatment is not available during pregnancy or breastfeeding, or for those with neuromuscular disorders.

Compare botox types

How does this differ from the others?

Compare the target tissue, onset, and duration against wrinkle, salivary, and skin botox in one place.

Consultation

Is muscle the reason for your jawline?

We check by palpation whether bone, fat, or muscle is the main factor, then guide you through the needed dose and treatment plan in a 1:1 consultation.