Jaw slimming is a non-surgical treatment that relaxes the masseter chewing muscle to slim and soften the lower face. Small injections of botulinum toxin reduce an overdeveloped masseter, creating a softer V-line and easing jaw clenching. It takes under 30 minutes with little downtime, and results last about 3 to 6 months. This guide explains how it works and what to expect in Bangkok.

Table of Contents

1. The Short Answer
2. What Is Jaw Slimming and How It Works
3. Who Is It Suitable For?
4. Results, Duration and Downtime
5. Jaw Slimming vs. Other Face-Slimming Options
6. Jaw Slimming Pricing at Bibi Clinic in Bangkok
7. Frequently Asked Questions

1. The Short Answer

Jaw slimming works by using small injections of botulinum toxin to relax the masseter muscles, the main chewing muscles located on either side of the jaw. In some people, these muscles become enlarged due to genetics, teeth grinding, or frequent chewing, which can make the lower face appear wider.

As the masseter muscles gradually relax over the following weeks, they typically reduce in size, creating a softer and more contoured V-line. Many patients also notice a reduction in jaw tension related to clenching or grinding. The treatment is temporary, with results generally lasting between 3 and 6 months. With ongoing treatments, the muscles may remain smaller for longer periods over time [1][2].

2. What Is Jaw Slimming and How It Works

Jaw slimming is an injection-based treatment that uses botulinum toxin to temporarily relax the masseter. The masseter is a powerful chewing muscle on either side of the jaw; when it becomes overdeveloped, it can make the lower face look wider or more square.

Botulinum toxin blocks the nerve signals that make the muscle contract, so it becomes less active and slowly reduces in bulk — the jawline takes on a slimmer shape often described as a V-line or ‘small face’ effect [1].

Onset is gradual: the toxin begins working within 2 to 3 days, with full results visible at about two weeks. Many patients also notice less jaw tension or grinding discomfort.

The treatment process

• Consultation: the doctor assesses masseter size and facial structure and confirms whether jaw slimming suits you
• Preparation: the area is cleaned and optional numbing cream applied; most find the injections tolerable
• Injection: precise points into the masseter, usually about 10 minutes
• Aftercare: return to normal activities immediately; avoid hard chewing, intense jaw exercise or massaging the area for 24 hours

Individual results vary.

3. Who Is It Suitable For?

Jaw slimming works best for specific concerns, and a consultation is always needed first. Good candidates include:

• Masseter hypertrophy — overdeveloped chewing muscles creating a square or wide lower face
• Bruxism — clenching or grinding that causes jaw pain or headaches
• Those wanting a softer, more oval or V-shaped jawline without surgery

Extra caution may be needed if you are pregnant or breastfeeding, have a neuromuscular condition, or have a known allergy to botulinum toxin products. In addition, if the width of your jaw is primarily due to your bone structure rather than enlarged masseter muscles, the degree of visible slimming may be more limited.

Whether this treatment is suitable for you, and the appropriate dose to use, should always be determined by a qualified physician following an individual assessment.

4. Results, Duration and Downtime

You may notice changes within 2 to 14 days, with full results at about two weeks once the masseter has relaxed and slightly reduced in bulk. Results generally last 3 to 6 months for first-time patients, and with repeated treatments the muscle may stay smaller for longer between sessions as it adapts to reduced activity [2].

There is no significant downtime — most people resume daily activities immediately. Mild redness or tenderness at the injection site may occur but usually settles within hours.

Possible side effects

• Temporary mild bruising or swelling at the injection points
• Short-term jaw stiffness or slight asymmetry (usually self-resolving)
• Rarely, difficulty chewing if too much product is used — a reason to choose an experienced doctor

Individual results vary.

5. Jaw Slimming vs. Other Face-Slimming Options

Jaw slimming is one of several ways to contour the lower face. The right option depends on the cause of your concern.

5. Jaw Slimming vs. Other Face-Slimming Options

Jaw slimming is one of several ways to contour the lower face. The right option depends on the cause of your concern.

Combinations are often most effective — for example, pairing jaw slimming with a small amount of chin filler can enhance the V-line. Individual results vary.

Combinations are often most effective — for example, pairing jaw slimming with a small amount of chin filler can enhance the V-line. Individual results vary.

6. Jaw Slimming Pricing at Bibi Clinic in Bangkok

Jaw slimming is priced by the brand of botulinum toxin and the number of units, which depend on your masseter size and goals.

The menu below is listed openly; your exact dose is confirmed at consultation, never estimated in advance.

Product / Brand	Units / Area	Price (THB)
Nabota (Korea)	1 area	2,980
Nabota (Korea)	50 units	5,980
Nabota (Korea)	100 units	11,960
Allergan (USA)	50 units	16,800
Allergan (USA)	100 units	29,800

At Bibi Clinic, treatment is physician-led, with a whole-face assessment and personalised dosing, and support in English, Japanese and Thai. For the full, current menu, see the anti-wrinkle injection treatment page.

7. Frequently Asked Questions

Is jaw slimming painful?

Most people describe a mild pinch. The needles are very fine and the session is quick, and a topical numbing cream can be applied if preferred. Discomfort is generally minimal and short-lived.

How long do results last?

Results typically last 3 to 6 months for first-time patients. With consistent repeat treatments, some find the effect holds slightly longer over time as the muscle gradually reduces in bulk.

Is there any downtime?

There is no downtime — you can return to work or daily activities immediately. Avoid hard chewing, intense jaw exercise or touching the injection area for about 24 hours.

Will my face look unnatural or frozen?

With the correct dose from an experienced doctor, jaw slimming should look natural. The goal is to slim the lower face, not immobilise it — you will still chew, speak and express normally.

Can it be combined with other treatments?

Yes — jaw slimming is commonly combined with chin or cheek filler, thread lift or skin boosters for a more complete result. Your doctor can advise on the best combination for your facial structure.

Considering Jaw Slimming in Bangkok?

If you are considering jaw slimming in Bangkok, Bibi Clinic offers a personalised consultation with an experienced aesthetic physician — in English, Japanese or Thai. Book a consultation →

References

[1] The Role of Botulinum Toxin for Masseter Muscle Hypertrophy: A Comprehensive Review. (2025)
Source: PubMed – The Role of Botulinum Toxin for Masseter Muscle Hypertrophy

[2] Efficacy of Botulinum Toxin in Masseter Hypertrophy: A 4-Year Follow-Up Study. (2019)
Source: PubMed – Efficacy of Botulinum Toxin in Masseter Hypertrophy

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Individual results vary. Please consult a qualified medical professional before undergoing any aesthetic treatment. Bibi Clinic’s physicians will assess your personal suitability during a consultation.