Masseter botox — botulinum toxin injected into the masseter muscle that closes the jaw — is the non-surgical V-line option for patients who don\'t want bone work. In Korea it is one of the most-performed cosmetic injections of any kind, requested for both jaw-line slimming and bruxism (clenching/grinding). It is highly effective in the right candidate, and disappointing in the wrong one. Here is how to tell which you are.
How it works
The masseter muscle attaches at the lower mandible and gives the lower face a square or rounded shape when hypertrophic. Botulinum toxin reduces contractile activity, the muscle gradually atrophies, and the lower-face contour softens over 6–12 weeks.
The procedure does not cut bone, does not affect skin, and is reversible — the muscle returns over months as the toxin wears off.
Who it works well for
- Hypertrophic masseters — visibly bulky when you clench, with a defined square jaw appearance.
- Bruxism / TMJ tension — bonus benefit on grinding, headaches, and jaw soreness.
- Patients seeking a softer jaw without surgery.
Who it disappoints
- Patients whose lower-face width is mostly bone, not muscle. Bone width does not respond to botulinum toxin.
- Patients with significant skin laxity. Reducing muscle volume in older skin can worsen sagging.
- Patients expecting permanent change. The effect is real but maintenance is required every 4–8 months.
A good consultation will assess masseter bulk by palpation and ask you to clench. If the muscle barely moves, the procedure has limited upside.
Dosing — the part that gets botched
Korean dermatology consensus dosing for cosmetic masseter is generally 25–40 units per side, with adjustments for muscle bulk. Common errors:
- Underdosing — clinics that quote bargain prices for "20 units total" deliver inadequate muscle relaxation; results disappoint.
- Overdosing — too high a dose can produce a hollowed lower face and an awkward smile, especially in thin patients.
- Asymmetric dosing — improper bilateral dosing can produce visible asymmetry.
Ask your clinic for unit-based dosing, not vial-based. "Two vials" tells you nothing without knowing dilution.
Timeline and longevity
- Day 1–7: no visible change yet.
- Week 2: mild softening of clenching strength.
- Week 4–6: visible reduction in jaw width during clench.
- Week 8–12: peak result.
- Month 4–6: effect plateaus and gradually declines.
- Repeat injection: typically every 4–6 months for the first 1–2 cycles, then 6–9 months as the muscle adapts.
Combination treatments
Many Korean clinics combine masseter botox with:
- Skin botox / microbotox for pore size and oil reduction in the same area.
- HIFU or RF tightening to address skin laxity that may emerge as the muscle reduces.
- Filler at the chin to elongate the chin point and complete the V-shape.
Combination strategies require experience — getting the relative dosing right is what separates a good Korean dermatologist from an average one.
Side effects to know about
- Smile change. Excessive masseter weakening can subtly affect smile mechanics for 1–2 months.
- Cheek sagging. Visible mostly in older patients with reduced skin elasticity.
- Chewing fatigue. Mild and temporary in the first few weeks.
- Bruising at injection sites. Resolves in 3–5 days.
2026 cost ranges in Gangnam
- Budget-tier package (Korean brand, mid-range dose): $200–$300 per session.
- Mid-tier (premium Korean brand, full dose): $300–$500.
- Premium-tier (imported brand, surgeon-administered): $500–$800.
What to ask in your consultation
- What is my dose per side, in units?
- Which Korean brand are you using, and why this one?
- How many cycles before you expect the muscle to plateau?
- What is your touch-up policy if results are asymmetric at week 4?
Masseter botox is one of the highest-satisfaction procedures in Korean aesthetic medicine — when the diagnosis is right and the dosing is honest. Ask the right questions and you are most of the way to a clean result.