Quick answer:
Jaw Botox involves injecting botulinum toxin into the masseter, the chewing muscle at the angle of the jaw. When the muscle relaxes and gradually shrinks, the lower face looks slimmer and softer. Slimming usually becomes visible after four to eight weeks, and repeat treatment every four to six months maintains the result.
What is masseter hypertrophy?
The masseter can enlarge from genetics, clenching, grinding (bruxism) or chewing habits. An enlarged masseter makes the lower face look square or wide. You can often feel it bulge when you clench your teeth.
Who is a good candidate?
- A square jaw caused mainly by muscle bulk
- Clenching or grinding that tires the jaw
- People wanting a softer, more oval lower face without surgery
It will not help much if width comes mainly from bone structure, fat or sagging skin. A broad jaw from fat may suit other treatments, and jowls from laxity may suit lifting.
What is the timeline?
- 1–2 weeks
– the muscle feels weaker when chewing hard foods.
- 4–8 weeks
– visible slimming as the muscle reduces in size.
- 3–6 months
– effect begins to fade; repeat treatment maintains results.
With repeated sessions, some people need treatment less often.
Side effects and risks
- Temporary chewing fatigue
- Mild bruising or tenderness
- Rarely, an uneven smile if toxin affects nearby muscles
- Occasionally, a slight hollow appearance or "jowl" accentuation if the muscle shrinks in someone with existing laxity
Jaw Botox vs other options
Salivary gland Botox targets the parotid gland behind the jaw, which can add fullness in some faces. Lifting devices address sagging rather than muscle. Fat-dissolving injections and microwave treatments target fat. Many people combine approaches when more than one factor contributes.
How a doctor checks if it suits you
- You clench your teeth while the doctor feels the angle of the jaw.
- A firm, bulging muscle suggests masseter hypertrophy.
- The doctor checks fat, skin laxity and salivary glands.
- Photos from the front and both sides help track change.
Dosing and brands
The masseter is a large muscle, so it needs more units than facial wrinkles. Doses depend on muscle size, strength and the product used. Some people with frequent, high-dose treatment choose products with fewer accessory proteins to reduce the theoretical risk of antibody resistance.
What to expect week by week
- Day 3–7
– chewing tough food may feel tiring.
- Week 2–4
– muscle feels softer when clenching.
- Week 4–8
– visible slimming at the jaw angle.
- Month 4–6
– muscle gradually strengthens again.
Tips for better results
- Avoid chewing gum and very hard foods for a few weeks.
- Manage daytime clenching; a dentist may suggest a night guard.
- Schedule repeat treatment before the muscle fully returns.
Who should combine treatments
If your jawline also has mild laxity, slimming the muscle can make soft tissue look slightly looser. In that case, a lifting device or thread lift may be planned after the muscle has reduced.
Frequently asked questions
Does jaw Botox hurt?
It is a few quick injections per side; most people find it mild.
Can it help teeth grinding?
It may reduce clenching force for some people; discuss this with a doctor or dentist.
How many units are used?
Doses vary by muscle size and product; the doctor will assess this.
References
- American Academy of Dermatology – Botulinum toxin therapy overview
This article is general information, not medical advice or a diagnosis. Suitability, recovery and results vary from person to person. Please consult a qualified doctor before any procedure.
