A wide or square jaw is most often caused by enlarged chewing muscles, the shape of your underlying bone, or both. The good news is that several proven options exist to slim the lower face, ranging from simple injections that take minutes to surgical procedures that permanently reshape the bone. Which approach makes sense depends on whether your jaw width comes from muscle, bone, or a combination.
Why Your Jaw Looks Wide
The biggest soft-tissue contributor to a wide lower face is the masseter, the powerful muscle on each side of your jaw that you can feel bulge when you clench your teeth. This muscle can enlarge well beyond its normal size, a condition called masseter hypertrophy, and it visibly squares off the face. Teeth grinding (bruxism), habitual gum chewing, clenching from stress or anxiety, and temporomandibular joint problems have all been linked to this enlargement. Some people simply inherit thicker masseters with no identifiable trigger. Masseter hypertrophy can be one-sided, creating facial asymmetry, or affect both sides equally.
Beyond muscle, the mandible itself plays a role. A naturally wide or prominent jaw angle, a broad chin, or both can make the lower face look heavy regardless of muscle size. Genetics determine bone structure, and no amount of lifestyle change will alter it. Understanding whether your jaw width is primarily muscular or skeletal is the first step, because the treatments are completely different.
Botox for Masseter Reduction
If enlarged chewing muscles are the main issue, injections of botulinum toxin (commonly known as Botox) into the masseter are the most popular non-surgical fix. The toxin partially relaxes the muscle, and over several weeks the muscle shrinks from disuse, the same way any muscle loses bulk when you stop working it. The effect is a noticeably slimmer jawline without any incisions or downtime.
Doses typically range from 20 to 30 units per side, though some practitioners start lower. Research shows that doses above 20 units per side reliably reduce muscle size and can maintain results for at least nine months. Most people notice peak slimming around three to six months after injection. The muscle then gradually regains its original thickness, so repeat treatments are usually needed once or twice a year to maintain the look. Each session takes about 10 to 15 minutes, and you can return to normal activities immediately.
Results vary depending on how much of your jaw width is muscular versus skeletal. If your bone structure is already wide, Botox will soften the appearance but won’t produce a dramatic change on its own.
Radiofrequency Ablation: A Longer-Lasting Alternative
A less well-known option is radiofrequency (RF) ablation of the masseter muscle. Instead of temporarily blocking nerve signals the way Botox does, RF uses heat to destroy a small portion of the muscle tissue. In a comparative study, masseter thickness continued to decrease steadily over 12 months after RF treatment, while Botox results had returned to baseline by that same point. The procedure didn’t cause infections or limit mouth opening in the study participants.
RF ablation isn’t as widely available as Botox and typically costs more per session, but it may appeal to people tired of repeat injections. Because the muscle tissue is permanently reduced rather than temporarily relaxed, fewer maintenance treatments are needed.
Surgical Jaw Reduction
When the bone itself is the source of width, surgery is the only option that produces a permanent change. The umbrella term for these procedures is mandibuloplasty, and several techniques exist depending on what needs to change.
Mandible angle reduction shaves or cuts the flared bone at the back corners of the jaw, removing the square silhouette. Narrowing genioplasty addresses the chin specifically: the surgeon makes a T-shaped cut, removes a central wedge of bone, and brings the two remaining segments together so the chin is physically narrower. V-line surgery combines both, contouring the jaw angles and reshaping the chin in a single operation to create a tapered, V-shaped lower face. An inverted V-shaped bone cut with central segment removal can reduce both chin width and height at the same time.
All of these procedures are performed through incisions inside the mouth, so there are no visible scars on the face. They require general anesthesia and are typically done by oral or maxillofacial surgeons or plastic surgeons who specialize in facial bone work.
What Recovery Looks Like
Surgical jaw reduction involves a meaningful recovery period. Swelling peaks around days two to three and then gradually decreases over the first few weeks. During the first week, you’ll be limited to liquids and very soft foods like yogurt, applesauce, and blended soups. Chewing is off the table entirely.
Between weeks two and four, swelling improves noticeably and you’ll start to see the new shape emerge, though the final result is still hidden under residual puffiness. Normal eating habits return gradually over one to three months, but hard and chewy foods should still be avoided during this window. Most people feel fully healed past the three-month mark, with final swelling resolved and eating and speaking feeling natural again.
Risks of Jaw Surgery
Because the nerve that provides sensation to your lower lip, chin, and gums runs through a canal inside the jawbone, any mandibular bone surgery carries a real risk of nerve injury. Surgical recordings taken during operations have shown that a majority of nerves experience some degree of damage during cutting, ranging from temporary conduction slowdowns to actual structural injury. About 20% of patients report abnormal sensations six months after surgery, and roughly 5% still experience nerve-related pain a full year out. For most people, sensation gradually returns to normal, but permanent numbness in the lower lip or chin is a known possibility.
Other risks include infection, asymmetry requiring revision surgery, and the general risks of general anesthesia. Choosing a surgeon with high-volume experience in facial bone contouring significantly reduces these odds.
Costs to Expect
Masseter Botox typically runs between $500 and $1,500 per session depending on the dose and provider, and you’ll need two to three sessions per year. Over time, the cumulative cost adds up.
Surgical jaw reduction is a larger upfront investment. Single-jaw procedures generally cost between $10,000 and $20,000, while more complex surgeries involving both the upper and lower jaw can reach $20,000 to $40,000. Additional procedures like chin implants or orthodontic adjustments may add another $1,000 to $5,000. Most cosmetic jaw surgeries are not covered by insurance.
Do Jaw Exercises or Devices Work?
Jaw exerciser devices and facial workout routines are heavily marketed as a way to sculpt the jawline, but the science does not support those claims. A case study analysis published in Cureus found no statistically significant change in jaw appearance, double chin reduction, jawline enhancement, or face and neck tightening from using these products. The chewing muscles these devices target have no direct effect on submental fat, skin elasticity, or bone structure.
In fact, exercising the masseter could make a wide jaw worse. If your jaw looks square because of muscle bulk, deliberately working that muscle with a chew toy is the opposite of what you want. It’s the equivalent of doing bicep curls to make your arms thinner. If anything, people seeking a slimmer jaw should reduce the load on their masseters by cutting back on gum chewing, addressing teeth grinding, and managing stress-related clenching.
Choosing the Right Approach
Start by identifying the source of your jaw width. Clench your teeth and feel the sides of your jaw. If the muscle bulges prominently and your jaw looks wider when you clench, masseter hypertrophy is likely a significant factor, and Botox is a reasonable first step. It’s low-risk, reversible, and gives you a preview of how a slimmer jaw would look before committing to anything permanent.
If your jaw feels hard and bony even when relaxed, with prominent corners you can trace with your fingers, the width is skeletal. Botox alone won’t address that. Surgical contouring becomes the primary option, though some people combine both: surgery for bone and Botox for residual muscle bulk.
Weight loss can also modestly slim the lower face by reducing fat deposits around the jawline, but it won’t change muscle or bone dimensions. For people with a genetically wide mandible, the realistic non-surgical options are limited to Botox for the muscular component and strategic hairstyling or makeup contouring for visual balance.