What Is a Square Jaw Caused by Masseter Hypertrophy?

A square jaw appearance can be caused by an enlarged masseter muscle, the strong chewing muscle located at the angle of the jaw. This condition, known as masseter hypertrophy, results in a bulky, wide lower face that can make the face appear boxy, heavy, or masculine—even in individuals with a naturally slim bone structure.

Key signs of masseter muscle hypertrophy include:

• A square or wide lower face when viewed from the front
• A bulky appearance around the jawline, especially when clenching or chewing
• Facial asymmetry if one side is larger
• A face that appears heavy, short, or less feminine
• Difficulty achieving a V-line profile despite weight loss or contouring makeup

What Is Masseter Muscle Reduction?

Masseter Muscle Reduction is a non-invasive or minimally invasive treatment that slims the jawline by reducing the size of the masseter muscle.

At Seoul Cheil Plastic Surgery, two primary approaches are offered:

1️⃣ Non-Surgical Masseter Reduction (Botox Injections)

• Botulinum toxin is injected directly into the masseter muscle
• Temporarily relaxes and weakens the muscle, leading to gradual atrophy
• Results typically visible within 4–6 weeks, lasting 4–6 months
• No downtime, minimal discomfort

2️⃣ Surgical Masseter Reduction

• For severe hypertrophy or long-term correction
• Involves partial removal or reshaping of the masseter muscle via an intraoral (inside the mouth) incision
• May be combined with mandible angle reduction for a slimmer, more defined jawline
• Surgery time: Approximately 1–1.5 hours under general anesthesia

Why Combine With Other Procedures?

For a complete V-line transformation, masseter reduction is often combined with:

• Mandibular angle reduction to slim the jawbone
• Chin reshaping (genioplasty) for improved proportions
• Buccal fat removal for cheek slimming
• Cheekbone reduction (malarplasty) for facial width balance

This holistic approach ensures a balanced, natural-looking result.

Key Characteristics of Masseter Hypertrophy

• A bulky jawline, especially when clenching
• A square, boxy face shape
• One side of the jaw appearing larger or more defined
• Difficulty achieving a slim, tapered V-line
• Jaw discomfort or tightness when chewing or talking

Can Fillers or Fat Dissolving Injections Fix a Bulky Jaw?

No. Fillers add volume, and fat dissolving injections only target fat cells, not muscle.
For true muscle hypertrophy, masseter reduction (Botox or surgery) is the only effective solution.

Masseter Muscle Reduction at Seoul Cheil Plastic Surgery

Seoul Cheil Plastic Surgery is a trusted leader in facial contouring treatments, offering both non-surgical Botox options and surgical masseter reduction for long-lasting, natural results.

Why patients choose Seoul Cheil:

• Over 20 years of expertise in facial contouring
• Advanced 3D facial analysis for customized treatment plans
• Safe, precise techniques for both Botox and surgical options
• Comprehensive post-op care for optimal results
• Multilingual staff for international patients

If you’re ready to achieve a slimmer, more feminine jawline, Masseter Muscle Reduction at Seoul Cheil Plastic Surgery can help you create the elegant, V-line profile you’ve always wanted.

Book your consultation today and take the first step toward a more refined you!

Preoperative Examination & Analysis

At SeoulCheil Plastic Surgery, your treatment begins with a one-stop visit. Our orthodontic and surgical team collaborate to analyze your facial structure and develop a personalized surgical plan tailored to your needs.

ASO vs. Double Jaw Surgery

ASO (Anterior Segmental Osteotomy) is designed to correct a protruding mouth by moving only the anterior segments of the jaw.
Double jaw surgery is intended for treating prognathism and involves repositioning the entire upper and lower jaw.

ASO is less invasive, does not require rubber band fixation, and allows for faster, safer recovery.

Why You Can Trust SeoulCheil Plastic Surgery

1. ASO Is Not a Major Surgery

With over 25 years of experience, ASO is a safe and routine procedure at our clinic. It is handled with precision and confidence.

2. Short and Precise Surgical Time

Most ASO surgeries are completed in under one hour. Our shortest recorded time is just 33 minutes.
While speed is not the priority, efficiency reflects surgical expertise and leads to less tissue trauma and faster recovery.

3. Fast Recovery

No intermaxillary fixation is needed. Patients can breathe, speak, and eat normally after surgery and usually return to their daily life within 3–4 days.

4. Academic and Clinical Excellence

Dr. Sang-Baek Han is a Seoul National University graduate and board-certified plastic surgeon with more than 25 years of clinical and research experience.

His paper on “Soft Tissue Response following Genioplasty Combined with ASO” was published in the internationally renowned PRS Journal in 2024 (Impact Factor 5.169).

He has been invited to speak at numerous global academic conferences, including PRS Korea, APS Korea, TSAPS (Taiwan), and Korea-Japan Joint Meetings.

5. Aesthetic Surgeon’s Eye

Dr. Han combines anatomical knowledge with an artistic approach to create beautiful and balanced results.
"A surgeon must also be an artist. Masterpieces aren’t made by tools—they’re shaped by hands."

6. Personalized Surgical Planning

Each patient receives a fully customized plan based on age, gender, facial structure, anatomical traits, lip thickness, philtrum length, and even social media trends.

Patients are welcome to bring photos of their desired appearance (e.g., celebrities), which are used as reference within medically safe limits.

7. Real Results You Can Watch

You can view video footage of real patients—before, immediately after, and months after surgery.

8. Patient-Centered Humanism

We never recommend unnecessary surgery.
We listen carefully, communicate clearly, and focus on delivering what each patient truly needs—both aesthetically and emotionally.

9. Transparent Surgery with CCTV

All surgeries are recorded via CCTV for transparency and peace of mind.
If requested, patients or their families may review the footage.

One mother commented after watching her daughter’s surgery:
"I was amazed to see how focused the doctor was for hours—standing still, shaping every detail with dedication."

10. Simultaneous Facial Bone Surgery

If necessary, ASO can be combined with cheekbone reduction and jaw angle contouring in one session.
The total operation takes approximately 3 hours and includes a one-night hospital stay—with no drainage tubes required.

11. One-Man Precision vs. Factory-Style Clinics

Unlike large clinics with multiple surgeons operating simultaneously, Dr. Han performs each surgery himself—ensuring personalized care, refined technique, and consistent results based on direct consultation and patient input.