Masseter Botox Side Effects Explained: Chewing Fatigue, Smile Changes and When to Call

The steak arrives, and about halfway through it she notices something odd. Her jaw is tired. Not sore in the old, grinding, wake-up-with-a-headache way she had the injections to manage, but tired, the way legs feel on the last flight of stairs. She puts the fork down, wonders whether this is normal, and reaches for her phone.

That small moment at a dinner table is where most questions about masseter botox side effects begin. The masseter is the thick muscle at the angle of the jaw, the one you can feel bulge when you clench. Softening it with botulinum toxin has become a common request for people with teeth grinding, jaw tension or a face shape they would like to look narrower.

What follows is an honest map of what can happen afterward, from the ordinary and expected to the rare and serious, and how to tell one from the other.

How masseter Botox actually works, in plain language

Botox is the brand name most people use as shorthand; the medicine itself is botulinum toxin type A, a purified protein made by a bacterium. Injected into a muscle, it blocks the chemical signal, acetylcholine, that nerves use to tell muscle fibers to contract. The nerve still fires. The muscle simply stops hearing it as clearly.

In the masseter, that means the fibers you use to clamp, grind and chew hard food contract with less force. Over weeks, a muscle that is asked to do less work loses some bulk, the same way a leg in a cast slims down. That is the whole idea: less clenching force for people who grind their teeth, and a softer jaw angle for people who want a narrower lower face.

The effect is not permanent. Nerve endings sprout new connections and the signal comes back. According to the Mayo Clinic, results generally begin one to three days after treatment, sometimes taking a week or more, and last around three to four months or longer depending on the problem being treated. The NHS describes a similar three-to-four-month window for cosmetic use.

Two features of this mechanism explain almost every side effect in this article. First, the toxin weakens whatever muscle it reaches, so if it drifts a centimeter past the masseter it weakens a neighbor. Second, weakness is dose- and placement-dependent, so a jaw that feels too soft in month one is doing exactly what the medicine does, just more than intended. Both problems are self-limiting because the drug itself is temporary.

Every decision about whether this approach suits you, and how it is planned, sits with a clinician who has examined your jaw, your bite and your medical history.

Why side effects happen: a one-minute tour of the jaw

Picture the side of your face as a small neighborhood of muscles living very close together. The masseter runs from the cheekbone down to the angle of the jaw. Sitting just in front of and above it are the muscles that lift the corner of the mouth and pull the cheek back when you smile, called the zygomaticus and the risorius. Draped over the lower masseter is the platysma, a thin sheet that runs down the neck. Behind and beneath it lies the parotid, the largest saliva-producing gland.

Botulinum toxin does not stay in a tidy pocket. It diffuses a short distance from where it is placed, and the amount of spread depends on volume, depth and the individual’s anatomy. Injections placed too high or too far forward can touch the smile muscles. Injections placed too shallow can weaken the platysma. Injections drifting backward can affect the parotid or, very rarely, deeper muscles involved in swallowing.

Anatomy also varies more than people expect. Masseter thickness differs between the left and right side in many faces. Some people have a masseter that sits lower, some higher; some chew mostly on one side and have built an asymmetric muscle without realizing it. A clinician who palpates the muscle while you clench, marks its borders, and asks about your chewing habits is mapping this neighborhood before injecting.

None of this makes side effects inevitable. It explains why the same medicine, in the same amount, can produce a perfectly ordinary result in one person and an uneven smile in another. The Mayo Clinic notes that the risk of adverse effects is lower when the procedure is performed by a clinician trained and experienced in the technique, which is a statement about anatomy as much as skill.

What are the risks of masseter Botox? The masseter botox side effects most people notice

Start with the ordinary. The masseter botox side effects most people actually experience are the same ones described for botulinum toxin injections anywhere on the face. The Mayo Clinic and MedlinePlus list pain, swelling or bruising at the injection site, headache, and flu-like symptoms in the first days. Because the masseter is a large, well-supplied muscle, a small bruise near the jaw angle is not unusual.

Then come the effects specific to the jaw:

• Chewing fatigue, especially with steak, crusty bread, nuts, chewy candy or gum. The muscle tires faster because part of it is off duty.
• A feeling that the bite is “different” or weaker in the first weeks, which usually settles as you adjust.
• Asymmetry, where one side softens more than the other.
• An altered or lopsided smile if the toxin reaches the neighboring smile muscles.
• Cheek hollowing, a flatter jaw angle than expected, or a sense of skin laxity, more likely in people with thinner skin or less facial fat.
• A small residual bulge when clenching, sometimes called a paradoxical bulge, when one portion of the muscle remains active while the rest relaxes.
• Temporary dryness of the mouth if the parotid gland is affected.

How likely are these? Consumer references from the Mayo Clinic, Cleveland Clinic and NHS agree that most reactions are mild and short-lived and that serious complications are rare, but they do not publish masseter-specific percentages, and neither should a magazine article. Published case series vary widely in how they count events, so any single number you see online is a snapshot of one clinic’s patients, not a universal rate.

The honest summary: the common effects are functional and cosmetic, they are temporary, and the rare ones are the reason a medical setting matters.

Chewing fatigue after masseter Botox: what it feels like and how long it usually lasts

Chewing fatigue is the side effect people are least prepared for, because nobody warns them that a jaw can feel like an overworked calf. It shows up somewhere between the first few days and the second week, matching the Mayo Clinic’s description of botulinum toxin taking effect over one to three days and sometimes a week or more.

It rarely feels like weakness at rest. You speak, sip coffee and eat soft food without noticing anything. The difference appears under load: a tough cut of meat, a baguette crust, a mouthful of almonds, a stubborn piece of caramel. The muscle simply gives out sooner than it used to, and you find yourself switching sides, taking smaller bites, or setting the food down for a moment.

The mechanism is straightforward. Botulinum toxin does not switch the masseter off; it reduces the number of fibers responding to the nerve. Fewer active fibers means the working ones reach exhaustion earlier. As the medicine’s effect fades over the following months, chewing endurance returns alongside it.

A few practical points patients report as helpful, none of which are medical instructions: choosing softer textures during the first weeks, cutting food into smaller pieces, and avoiding gum, which is essentially a prolonged endurance test for the masseter. If fatigue is severe enough to make ordinary meals difficult, that is worth reporting to the injector rather than pushing through, because it can signal that the muscle was weakened more than intended.

What chewing fatigue should not do is spread. Difficulty swallowing, liquids going down the wrong way, or a voice that sounds different are not chewing fatigue. They point to effects on deeper muscles and belong in the red-flag list at the end of this article.

Smile changes after masseter Botox: why a "different" smile happens

Of all the masseter botox side effects, a changed smile is the one that unsettles people most, because a smile is identity. The good news is that it has a clear anatomical explanation and a predictable end.

The muscles that lift the corners of the mouth and pull the cheeks outward sit just above and in front of the masseter’s upper border. If toxin is placed too high, too far forward or in a way that lets it diffuse into that zone, those muscles weaken. The result can be a smile that looks flatter on one side, a corner of the mouth that does not rise as far, or a grin that feels stiff, as though the face is smiling from the inside and the outside has not caught up.

Sometimes the change is subtler and reflects the masseter itself. A very relaxed masseter changes how the cheek moves over the jaw, and people occasionally describe a smile that looks “wider” or “lower” even when the smile muscles are untouched. Facial fat that used to sit on a firm muscle now sits on a softer one and shifts differently when you laugh.

There is no medicine that reverses botulinum toxin once it has bound to the nerve ending. The smile returns as the effect wears off, on the same three-to-four-month timeline the Mayo Clinic and NHS describe for the medicine as a whole, with partial improvement usually noticeable earlier. Some clinicians offer small adjustment injections to balance the opposite side; whether that is wise depends on the individual face and is a decision for the treating team.

Photographs help. Taking a relaxed and a full-smile photo before treatment gives you and your clinician a baseline, so that a perceived change can be compared with what your smile actually looked like beforehand.

Masseter Botox gone wrong? Sagging, jowls, hollowing and asymmetry

Search for “masseter botox gone wrong” and you will find alarming photographs and very little context. Most of what those images show falls into four categories, and each has a mechanism.

Sagging and jowling. The masseter acts like a firm shelf beneath the lower cheek. When it shrinks, skin and fat that rested on that shelf have less support. In a person with thick skin and good elasticity, the change reads as a slimmer jaw. In someone with thinner skin, less facial fat, or age-related laxity, the same shrinkage can read as softness along the jawline. The muscle has not damaged the skin; the scaffolding beneath it has changed.

Hollowing. When more of the muscle relaxes than the face can spare, the area in front of the ear and below the cheekbone can look sunken. This is more common in people who already had a lean face and asked for slimming they did not need.

Asymmetry. Masseters are rarely twins. If one side was thicker to begin with, or one side receives more toxin, or one side simply responds more, the jaw can look uneven for a period.

Paradoxical bulge. Occasionally a strip of the masseter, often near the front or top, keeps working while the rest relaxes, producing a small lump when clenching. It is cosmetic, not dangerous, and resolves as the medicine wears off or with a small adjustment placed by the clinician.

What connects these outcomes is that they are usually a mismatch between goal and anatomy, not a toxic reaction. They reverse over months. A careful assessment of skin quality, facial fat and muscle symmetry before treatment is the single most useful safeguard, and it is precisely the part of the process that online photographs cannot show.

Rare but serious: spread beyond the jaw and allergic reactions

Botulinum toxin products carry a warning from regulators about the possibility of the toxin spreading beyond the injection site and producing effects resembling botulism. This is rare, and MedlinePlus and the Mayo Clinic describe it consistently: the toxin can, in unusual cases, affect muscles far from where it was injected, causing generalized muscle weakness, double or blurred vision, drooping eyelids, hoarseness, trouble speaking clearly, trouble swallowing, difficulty breathing, or loss of bladder control. These symptoms can appear hours to weeks after treatment.

Why does the jaw deserve particular attention? The masseter is close to the muscles that move food to the back of the throat and to the parotid gland, and the amounts used for a bulky chewing muscle are larger than those used for a forehead line. Swallowing difficulty, food or liquid going down the wrong way, or a voice that sounds different are therefore the specific symptoms to watch. The Mayo Clinic advises calling a doctor right away if any of these occur after treatment.

Allergic reactions are a separate category. MedlinePlus lists rash, itching, hives, wheezing, and swelling of the face, lips or throat as reasons to seek emergency help. True allergy to botulinum toxin is uncommon, but it is treated like any other drug allergy: immediately, and in a medical setting.

Two further points belong here. Botulinum toxin is not recommended during pregnancy or breastfeeding, and people with certain neuromuscular conditions, such as myasthenia gravis or ALS, face higher risk of exaggerated weakness, according to the Mayo Clinic. Some antibiotics and other medicines can increase the toxin’s effect, which is why a complete medication list matters before treatment. These are conversations for the prescribing clinician, not decisions to make at home.

Does masseter Botox cause bone loss? What the evidence actually shows

This is the question with the most frightening headlines and the least settled science, so it deserves precision.

The concern rests on a real principle. Bone remodels in response to the forces placed on it. Muscles pull on bone, and when a muscle is weakened for a long time, the bone it attaches to can lose density; this is well established in limbs after casting or paralysis. The masseter attaches to the lower jaw, so it is reasonable to ask whether repeatedly weakening it changes the bone beneath.

What the research shows is layered. Animal studies, mostly in rodents and rabbits, have reported reduced bone density and altered shape in the jaw after repeated botulinum toxin injections into the masseter, sometimes with changes at the joint surface. Human studies are far fewer, smaller and less consistent. Some imaging studies have detected measurable reductions in bone density at the jaw angle after repeated treatment; others have found no meaningful change or have been too short to judge. Whether these measurements translate into fractures, dental problems or joint disease in people has not been demonstrated.

Consumer health references from the Mayo Clinic, Cleveland Clinic and NHS do not currently list jaw bone loss among the recognized side effects of botulinum toxin, which reflects the state of the evidence rather than a verdict of safety. The honest position is uncertainty: a plausible mechanism, supportive animal data, and thin human data.

Practical implications follow from that. People considering repeated masseter treatment over many years, those with osteoporosis or conditions affecting bone, and those with existing jaw joint disease should raise this specifically with their clinician and dentist. Spacing treatments as far apart as the goal allows, rather than re-treating on a fixed schedule, is a reasonable conversation to have while the science catches up.

Who masseter Botox is usually for, and who is usually asked to wait

Two broad groups ask about this treatment. The first has a functional problem: bruxism, the medical term for grinding or clenching the teeth, often at night; jaw pain or fatigue; tension headaches that start in the jaw; or worn, cracked or sensitive teeth traced back to clenching. The Cleveland Clinic lists botulinum toxin injections among the options a dentist or physician may consider for bruxism when other measures have not helped, alongside night guards, stress management and correcting bite problems.

The second group has a cosmetic goal: a jaw that looks wide or square because of a bulky masseter, which the treatment can soften over several months. In both groups, the best candidates share a feature: the masseter itself is doing the work. A wide jaw caused by bone rather than muscle will not narrow, and jaw pain caused by joint damage rather than muscle tension may not improve.

People are usually asked to wait, or to consider other options first, in several situations:

• Pregnancy, planning a pregnancy, or breastfeeding, where botulinum toxin is not recommended.
• Neuromuscular conditions such as myasthenia gravis, Lambert-Eaton syndrome or ALS.
• Active infection or skin problems at the injection site.
• A previous allergic reaction to any botulinum toxin product.
• Certain medicines that can enhance the toxin’s effect, including some antibiotics and muscle relaxants.
• Unrealistic expectations, such as wanting a dramatically different face shape from a single treatment, or wanting slimming in a face that is already lean.

A clinician will also want to know about jaw joint disorders, recent dental work, bleeding tendencies and blood-thinning medicines, which increase bruising. None of these are automatic exclusions. They are the reasons a consultation should feel like a medical assessment and not a menu.

Masseter Botox timeline: what the days and weeks afterward usually look like

Timelines below are typical ranges drawn from the Mayo Clinic, NHS and Cleveland Clinic descriptions of botulinum toxin, not promises. Individual response varies with muscle bulk, metabolism and technique.

Period	What is commonly experienced	What it usually means
First hours	Small tender bumps, mild swelling, possible pinpoint bruise at the jaw angle	Local needle effect; settles within days
Days 1 to 3	Headache or flu-like tiredness in some people; first hint of a softer clench	Toxin beginning to act (Mayo Clinic: onset one to three days, sometimes a week or more)
Week 1 to 2	Chewing fatigue with tough foods; any smile change or asymmetry becomes apparent	Muscle weakening reaching full effect (Cleveland Clinic: up to about two weeks)
Weeks 3 to 8	Gradual visible slimming of the jaw angle; fatigue eases as habits adjust	Muscle losing bulk from reduced use; timing here is clinician experience rather than a guideline figure
Months 3 to 4	Clench strength returning; softness fades; smile and symmetry normalize	Nerve endings re-establishing signal (Mayo Clinic and NHS: three to four months, sometimes longer)
Beyond	Muscle regains bulk if clenching resumes	Effects are reversible; repeat treatment is a fresh decision each time

Two patterns catch people out. Cosmetic slimming lags well behind functional weakness, so a jaw that feels different in week two may not look different until well into the second month. The return, likewise, is gradual: strength creeps back before shape does, which is why some people notice grinding again before they notice a wider jaw.

Most clinicians ask for a review around the two-week mark, when the effect is established and any unevenness can be assessed. That appointment is the right place to raise fatigue, smile changes or asymmetry, rather than searching for answers online at midnight.

Do dentists recommend masseter Botox? Where it sits among the alternatives

Some do, in specific circumstances; many prefer to start elsewhere. That range of opinion reflects the evidence rather than a turf dispute.

For bruxism, the Mayo Clinic and Cleveland Clinic describe a stepped approach. First comes identifying causes: stress and anxiety, sleep disorders such as sleep apnea, certain medicines, caffeine, alcohol and tobacco, and bite problems. Then come protective and behavioral measures: a custom night guard fitted by a dentist to shield the teeth, awareness training to catch daytime clenching, sleep hygiene, and stress management. Physical therapy and jaw relaxation exercises are often part of this. Botulinum toxin is listed as an option for severe bruxism that has not responded to other measures, and the Mayo Clinic notes that while some studies suggest it may help, more research is needed to establish its long-term safety and effectiveness for this purpose.

That is a measured position, and it explains dentists’ caution. Botulinum toxin reduces the force of clenching but does not address why the clenching happens. A night guard protects enamel indefinitely; the toxin wears off. Dentists also weigh the bone-density question discussed earlier and the risk of chewing weakness in people whose teeth are already compromised.

For jaw joint disorders, the Mayo Clinic describes botulinum toxin as one of several possible treatments, again with the same call for more evidence. For cosmetic jaw slimming, the alternatives are surgical procedures to reshape the jaw bone or reduce the muscle, which carry their own, larger risks, and simply accepting the face as it is.

The most useful conversation involves both a dentist and the injecting clinician, particularly if you have worn teeth, crowns, implants or a joint disorder. A dentist can tell you whether your teeth show the signs of clenching that the treatment is meant to address, and whether a guard alone might do the job.

What people often get wrong about masseter botox side effects

Myth: “If something goes wrong, my face is changed forever.” Botulinum toxin does not permanently alter muscle, nerve or skin. Every effect described in this article, welcome or not, fades as the nerve endings recover, on the three-to-four-month timescale the Mayo Clinic and NHS describe. What can persist is a change in habit: people who stop clenching may keep a slimmer muscle simply because they use it less.

Myth: “Chewing weakness means the injection was botched.” Some chewing fatigue is the expected result of weakening a chewing muscle. It becomes a concern only when ordinary meals are difficult or when it comes with swallowing or speech changes.

Myth: “The jaw looks slimmer within days.” The clench softens within days; the visible slimming takes weeks because the muscle has to shrink from disuse. Judging the result at day five is judging a race at the first corner.

Myth: “More toxin gives a better, longer result.” Beyond what is needed to relax the muscle, more product mainly increases the risk of hollowing, sagging and spread to neighbors. Longevity depends more on individual biology than quantity.

Myth: “Bone loss is proven, so the treatment is dangerous,” or its mirror, “bone loss is a myth.” The evidence is unsettled: consistent animal data, sparse and mixed human data, and no demonstrated harm to teeth or jaw function in people. Both certainties overstate what is known.

Myth: “A dentist and a cosmetic injector will always disagree.” They often agree on the basics and differ on where the treatment belongs in the sequence. Asking both is not shopping for a yes; it is gathering the full picture.

Myth: “Side effects mean I should never try again.” Sometimes an uneven smile reflects placement that can be adjusted; sometimes it reflects anatomy that makes the treatment a poor fit. Only an examination can tell the difference, and the decision rests with the treating team.

Questions to ask your care team before masseter Botox

A good consultation should leave you with fewer questions than you arrived with. These are the ones worth bringing, grouped by what they reveal.

About your suitability:

• Is my jaw width mainly muscle, bone or fat? What did you find when you felt the masseter while I clenched?
• Do my teeth show signs of clenching, and have I tried a night guard or other measures first?
• Do any of my medicines, health conditions or plans for pregnancy change the picture?
• Given my skin thickness and facial fat, am I someone who could look hollow or saggy rather than slimmer?

About the plan:

• How will you map the masseter’s borders and stay clear of the smile muscles and the parotid gland?
• How do you handle asymmetry between my two sides?
• Would you prefer to start conservatively and reassess, and when would that review be?

About what comes after:

• What chewing changes should I expect in the first two weeks, and what would be more than expected?
• Which symptoms mean I should call you the same day, and which mean I should go to an emergency department?
• If my smile changes, what are my options and how long would it take to settle on its own?
• How far apart would you space repeat treatments, and how do you think about the bone-density question over years?

About the setting:

• What is your training in facial anatomy and in managing complications from botulinum toxin?
• Is there a clinician available to speak to if I have a problem outside appointment hours?

Notice that none of these ask for a guarantee. Botulinum toxin is a medicine with a mechanism, not a promise, and a clinician who answers with mechanisms rather than assurances is telling you something reassuring about how they practice.

When to call your doctor after masseter Botox

Most of what you will notice after treatment belongs to the ordinary column: a bruise, a tender spot, a jaw that tires on tough food. Those settle on their own. A smaller set of symptoms needs a same-day call to the clinician who treated you, and a very small set needs emergency care.

Call the clinician who treated you promptly if you notice:

• A smile that has become noticeably uneven, or a corner of the mouth that no longer lifts.
• Chewing weakness severe enough that ordinary meals are hard.
• Marked asymmetry of the jaw, a new lump when clenching, or sagging that concerns you.
• Persistent or worsening pain, warmth, redness or swelling at an injection site, which can signal infection.
• A dry mouth that does not improve, or swelling in front of the ear.
• Any side effect that has not begun to ease by the two-week review.

Seek emergency care, or call emergency services, if you experience any of the following at any point in the hours to weeks after treatment, as described by the Mayo Clinic and MedlinePlus:

• Difficulty swallowing, choking on liquids, or food going down the wrong way.
• Difficulty breathing or shortness of breath.
• Slurred or hoarse speech, or trouble speaking clearly.
• Generalized muscle weakness, drooping eyelids, or double or blurred vision.
• Loss of bladder control.
• Signs of an allergic reaction: hives, widespread rash, wheezing, or swelling of the face, lips or throat.

These serious symptoms are rare. They are listed here because the jaw is close to the muscles of swallowing, and because the correct response to any of them is fast medical assessment, not waiting to see. Tell the treating clinicians exactly which product you received and when, so the team can judge whether the toxin is the likely cause. Everything about what happens next, including whether and when further treatment is appropriate, is a decision for them.

Frequently asked questions

What are the risks of masseter Botox?

The common risks are mild and temporary: bruising, tenderness or swelling at the jaw angle, headache, and chewing fatigue with tough foods. Less common effects include an uneven smile, asymmetry, cheek hollowing or sagging, and a residual bulge when clenching. Rare serious risks are spread of the toxin causing swallowing, speech or breathing difficulty, and allergic reactions, both of which need urgent medical care.

How likely is it for masseter Botox to go wrong?

Serious complications are rare, according to the Mayo Clinic, Cleveland Clinic and NHS, while mild effects such as bruising or chewing fatigue are common and expected. No reliable masseter-specific percentage exists in consumer health references, and figures quoted online usually come from single clinics with different ways of counting events. Careful anatomical assessment by a trained clinician is the main factor that lowers risk.

Do dentists recommend masseter Botox?

Some dentists consider it for severe bruxism that has not responded to night guards, stress management and correction of bite or sleep problems, and the Cleveland Clinic lists it among such options. Many prefer to start with those measures because the toxin reduces clenching force temporarily without addressing its cause. The Mayo Clinic notes more research is needed on its long-term use for grinding.

Will my face ever go back to normal after masseter Botox?

Yes, in the sense that botulinum toxin does not permanently change muscle, nerve or skin. Strength, smile and symmetry return as the effect fades over roughly three to four months, according to the Mayo Clinic and NHS, with shape following more slowly as the muscle regains bulk. People who stop clenching may keep a slimmer muscle simply from using it less.

What are the side effects of Botox for jaw clenching?

When used for jaw clenching, the side effects mirror those for cosmetic slimming: tenderness, bruising, headache, and reduced chewing endurance with hard or chewy foods. Because the aim is to weaken the clench, some loss of bite force is expected rather than a complication. A changed smile, asymmetry or sagging can also occur, and swallowing or speech difficulty is a rare warning sign needing urgent care.

Does masseter Botox cause bone loss in the jaw?

The evidence is unsettled. Animal studies consistently show reduced jaw bone density after repeated masseter injections, but human studies are few, small and mixed, and no link to fractures, dental problems or joint disease in people has been demonstrated. Major consumer health references do not currently list jaw bone loss as a recognized side effect. Raising the question with your clinician and dentist is reasonable.

How long does chewing fatigue last after masseter Botox?

Chewing fatigue usually begins within the first one to two weeks as the toxin takes effect and gradually eases as the medicine wears off over about three to four months, the timeline the Mayo Clinic describes for botulinum toxin generally. Many people find it most noticeable in the first month and adapt by choosing softer textures. Fatigue that makes ordinary meals difficult should be reported to the injector.

Why did my smile change after masseter Botox?

A changed smile usually means some toxin reached the muscles that lift the mouth corners and pull the cheeks back, which sit just above and in front of the masseter. Occasionally a very relaxed masseter changes how the cheek moves, making the smile look wider or lower. Either way the effect is temporary and resolves as the medicine wears off; your clinician can assess whether a small adjustment is appropriate.

Can masseter Botox cause sagging or jowls?

It can, particularly in people with thinner skin, less facial fat or age-related laxity. The masseter supports the lower cheek, and when it shrinks, skin and fat above it have less to rest on. In firmer, fuller faces the same change reads as a slimmer jaw. The effect is temporary, but assessing skin quality and facial fat before treatment is the best way to avoid it.

Who should not have masseter Botox?

Botulinum toxin is not recommended during pregnancy or breastfeeding, and people with neuromuscular conditions such as myasthenia gravis or ALS face a higher risk of exaggerated weakness, according to the Mayo Clinic. A previous allergic reaction to any botulinum toxin product, active infection at the site, and certain medicines that enhance the toxin’s effect also require caution. The treating clinician makes the final judgment.

References

• MedlinePlus: Botox
• Cleveland Clinic: Botulinum toxin injections
• Cleveland Clinic: Teeth grinding (bruxism)

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.